142 results on '"Head movements"'
Search Results
2. Temporal interpolation alters motion in fMRI scans: Magnitudes and consequences for artifact detection.
- Author
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Power, Jonathan, Plitt, Mark, Kundu, Prantik, Bandettini, Peter, and Martin, Alex
- Subjects
Artifacts ,Head Movements ,Humans ,Image Processing ,Computer-Assisted ,Magnetic Resonance Imaging ,Quality Control - Abstract
Head motion can be estimated at any point of fMRI image processing. Processing steps involving temporal interpolation (e.g., slice time correction or outlier replacement) often precede motion estimation in the literature. From first principles it can be anticipated that temporal interpolation will alter head motion in a scan. Here we demonstrate this effect and its consequences in five large fMRI datasets. Estimated head motion was reduced by 10-50% or more following temporal interpolation, and reductions were often visible to the naked eye. Such reductions make the data seem to be of improved quality. Such reductions also degrade the sensitivity of analyses aimed at detecting motion-related artifact and can cause a dataset with artifact to falsely appear artifact-free. These reduced motion estimates will be particularly problematic for studies needing estimates of motion in time, such as studies of dynamics. Based on these findings, it is sensible to obtain motion estimates prior to any image processing (regardless of subsequent processing steps and the actual timing of motion correction procedures, which need not be changed). We also find that outlier replacement procedures change signals almost entirely during times of motion and therefore have notable similarities to motion-targeting censoring strategies (which withhold or replace signals entirely during times of motion).
- Published
- 2017
3. Automated Movement Correction for Dynamic PET/CT Images: Evaluation with Phantom and Patient Data
- Author
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Ye, Hu, Wong, Koon-Pong, Wardak, Mirwais, Dahlbom, Magnus, Kepe, Vladimir, Barrio, Jorge R, Nelson, Linda D, Small, Gary W, and Huang, Sung-Cheng
- Subjects
Medical and Biological Physics ,Biomedical and Clinical Sciences ,Clinical Sciences ,Physical Sciences ,Oncology and Carcinogenesis ,Biomedical Imaging ,Bioengineering ,Cancer ,Neurosciences ,Clinical Research ,4.1 Discovery and preclinical testing of markers and technologies ,Detection ,screening and diagnosis ,Automation ,Fluorodeoxyglucose F18 ,Head Movements ,Humans ,Image Processing ,Computer-Assisted ,Nitriles ,Phantoms ,Imaging ,Positron-Emission Tomography ,Retrospective Studies ,Tomography ,X-Ray Computed ,General Science & Technology - Abstract
Head movement during a dynamic brain PET/CT imaging results in mismatch between CT and dynamic PET images. It can cause artifacts in CT-based attenuation corrected PET images, thus affecting both the qualitative and quantitative aspects of the dynamic PET images and the derived parametric images. In this study, we developed an automated retrospective image-based movement correction (MC) procedure. The MC method first registered the CT image to each dynamic PET frames, then re-reconstructed the PET frames with CT-based attenuation correction, and finally re-aligned all the PET frames to the same position. We evaluated the MC method's performance on the Hoffman phantom and dynamic FDDNP and FDG PET/CT images of patients with neurodegenerative disease or with poor compliance. Dynamic FDDNP PET/CT images (65 min) were obtained from 12 patients and dynamic FDG PET/CT images (60 min) were obtained from 6 patients. Logan analysis with cerebellum as the reference region was used to generate regional distribution volume ratio (DVR) for FDDNP scan before and after MC. For FDG studies, the image derived input function was used to generate parametric image of FDG uptake constant (Ki) before and after MC. Phantom study showed high accuracy of registration between PET and CT and improved PET images after MC. In patient study, head movement was observed in all subjects, especially in late PET frames with an average displacement of 6.92 mm. The z-direction translation (average maximum = 5.32 mm) and x-axis rotation (average maximum = 5.19 degrees) occurred most frequently. Image artifacts were significantly diminished after MC. There were significant differences (P
- Published
- 2014
4. Measurement and correction of microscopic head motion during magnetic resonance imaging of the brain.
- Author
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Maclaren, Julian, Armstrong, Brian SR, Barrows, Robert T, Danishad, KA, Ernst, Thomas, Foster, Colin L, Gumus, Kazim, Herbst, Michael, Kadashevich, Ilja Y, Kusik, Todd P, Li, Qiaotian, Lovell-Smith, Cris, Prieto, Thomas, Schulze, Peter, Speck, Oliver, Stucht, Daniel, and Zaitsev, Maxim
- Subjects
Humans ,Magnetic Resonance Imaging ,Calibration ,Head Movements ,Image Processing ,Computer-Assisted ,Software ,Neuroimaging ,Image Processing ,Computer-Assisted ,General Science & Technology - Abstract
Magnetic resonance imaging (MRI) is a widely used method for non-invasive study of the structure and function of the human brain. Increasing magnetic field strengths enable higher resolution imaging; however, long scan times and high motion sensitivity mean that image quality is often limited by the involuntary motion of the subject. Prospective motion correction is a technique that addresses this problem by tracking head motion and continuously updating the imaging pulse sequence, locking the imaging volume position and orientation relative to the moving brain. The accuracy and precision of current MR-compatible tracking systems and navigator methods allows the quantification and correction of large-scale motion, but not the correction of very small involuntary movements in six degrees of freedom. In this work, we present an MR-compatible tracking system comprising a single camera and a single 15 mm marker that provides tracking precision in the order of 10 m and 0.01 degrees. We show preliminary results, which indicate that when used for prospective motion correction, the system enables improvement in image quality at both 3 T and 7 T, even in experienced and cooperative subjects trained to remain motionless during imaging. We also report direct observation and quantification of the mechanical ballistocardiogram (BCG) during simultaneous MR imaging. This is particularly apparent in the head-feet direction, with a peak-to-peak displacement of 140 m.
- Published
- 2012
5. Interpersonal coordination analysis in bat-and-ball sports under a real game situation: Asymmetric interaction and delayed coupling.
- Author
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Takamido R, Yokoyama K, Nakamoto H, Ota J, and Yamamoto Y
- Subjects
- Animals, Psychomotor Performance, Biomechanical Phenomena, Head Movements, Chiroptera, Baseball
- Abstract
This study investigated the interpersonal coordination between the pitcher and the batter in bat-and-ball sports. Although the importance of interpersonal coordination is widely accepted in many sports, no studies have investigated it in bat-and-ball sports because the dominant task constraints surrounding the interaction between pitcher and batter make it difficult to apply conventional analytic techniques. To address the issue, this study proposes a new analytical framework to investigate interpersonal coordination in bat-and-ball sports under a real game situation with two main characteristics: asymmetric interaction and delayed coupling. First, the dynamic time warping technique was used to evaluate the stability of the head movement pattern of the pitcher and batter, and cross-correlation analysis was used to quantify the temporal relationship between them. We found that the head movement pattern of batters was significantly more unstable than that of pitchers, and approximately 60% of the variance of the change in the head movement pattern of batters could be explained by that of the pitchers. Moreover, expert batters followed a pitcher's movements with a specific time delay of approximately 250 ms. These findings highlight the characteristics of interpersonal coordination in bat-and-ball sports: the pitcher can make a pre-patterned stable motion, whereas the batter needs to follow and adjust their movement to it. Although the effects of prediction ability need to be investigated to understand its detailed mechanism, the contribution of this study is that it revealed the existence of the interpersonal coordination between the pitcher and batter of bat-and-ball sports under a real game situation., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Takamido et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
- Published
- 2023
- Full Text
- View/download PDF
6. Spontaneous head movements support accurate horizontal auditory localization in a virtual visual environment
- Author
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Andrea Gulli, Federico Fontana, Eva Orzan, Alessandro Aruffo, and Enrico Muzzi
- Subjects
Multidisciplinary ,Auditory-motor rehabilitation ,Head Movements ,Auditory localization ,Virtual reality ,Perception and action task ,Humans ,Sound Localization ,Child - Abstract
This study investigates the relationship between auditory localization accuracy in the horizontal plane and the spontaneous translation and rotation of the head in response to an acoustic stimulus from an invisible sound source. Although a number of studies have suggested that localization ability improves with head movements, most of them measured the perceived source elevation and front-back disambiguation. We investigated the contribution of head movements to auditory localization in the anterior horizontal field in normal hearing subjects. A virtual reality scenario was used to conceal visual cues during the test through a head mounted display. In this condition, we found that an active search of the sound origin using head movements is not strictly necessary, yet sufficient for achieving greater sound source localization accuracy. This result may have important implications in the clinical assessment and training of adults and children affected by hearing and motor impairments.
- Published
- 2022
7. Efficient training approaches for optimizing behavioral performance and reducing head fixation time
- Author
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Anna Nasr, Sina E. Dominiak, Keisuke Sehara, Mostafa A. Nashaat, Robert N. S. Sachdev, and Matthew E. Larkum
- Subjects
Mice ,Multidisciplinary ,Behavior, Animal ,Head Movements ,Animals ,Learning - Abstract
The use of head fixation has become routine in systems neuroscience. However, whether the behavior changes with head fixation, whether animals can learn aspects of a task while freely moving and transfer this knowledge to the head fixed condition, has not been examined in much detail. Here, we used a novel floating platform, the “Air-Track”, which simulates free movement in a real-world environment to address the effect of head fixation and developed methods to accelerate training of behavioral tasks for head fixed mice. We trained mice in a Y maze two choice discrimination task. One group was trained while head fixed and compared to a separate group that was pre-trained while freely moving and then trained on the same task while head fixed. Pre-training significantly reduced the time needed to relearn the discrimination task while head fixed. Freely moving and head fixed mice displayed similar behavioral patterns, however, head fixation significantly slowed movement speed. The speed of movement in the head fixed mice depended on the weight of the platform. We conclude that home-cage pre-training improves learning performance of head fixed mice and that while head fixation obviously limits some aspects of movement, the patterns of behavior observed in head fixed and freely moving mice are similar.
- Published
- 2022
8. Eye and head movements while encoding and recognizing panoramic scenes in virtual reality.
- Author
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Bischof WF, Anderson NC, and Kingstone A
- Subjects
- Humans, Eye Movements, Recognition, Psychology, Photic Stimulation methods, Head Movements, Virtual Reality
- Abstract
One approach to studying the recognition of scenes and objects relies on the comparison of eye movement patterns during encoding and recognition. Past studies typically analyzed the perception of flat stimuli of limited extent presented on a computer monitor that did not require head movements. In contrast, participants in the present study saw omnidirectional panoramic scenes through an immersive 3D virtual reality viewer, and they could move their head freely to inspect different parts of the visual scenes. This allowed us to examine how unconstrained observers use their head and eyes to encode and recognize visual scenes. By studying head and eye movement within a fully immersive environment, and applying cross-recurrence analysis, we found that eye movements are strongly influenced by the content of the visual environment, as are head movements-though to a much lesser degree. Moreover, we found that the head and eyes are linked, with the head supporting, and by and large mirroring the movements of the eyes, consistent with the notion that the head operates to support the acquisition of visual information by the eyes., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Bischof et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
- Published
- 2023
- Full Text
- View/download PDF
9. Adapting the coordination of eyes and head to differences in task and environment during fully-mobile visual exploration
- Author
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Gabrielle Blanch, Brianna McGee, and John M. Franchak
- Subjects
genetic structures ,Eye Movements ,Inertia ,Head (linguistics) ,Computer science ,Physiology ,Visual System ,Vision ,Sensory Physiology ,Social Sciences ,Walking ,Task (project management) ,Fully mobile ,Human–computer interaction ,Medicine and Health Sciences ,Psychology ,Multidisciplinary ,Eye Lens ,Movement (music) ,Physics ,Classical Mechanics ,Cameras ,Sensory Systems ,Optical Equipment ,Head Movements ,Physical Sciences ,Medicine ,Engineering and Technology ,Sensory Perception ,Anatomy ,Research Article ,Science ,Ocular Anatomy ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Equipment ,Fixation, Ocular ,Motion ,Inertial measurement unit ,Ocular System ,Biological Locomotion ,Cognitive Psychology ,Eye movement ,Biology and Life Sciences ,Gaze ,eye diseases ,Eye tracking ,Eyes ,Cognitive Science ,Perception ,Head ,Psychomotor Performance ,Neuroscience - Abstract
How are eyes and head adapted to meet the demands of visual exploration in different tasks and environments? In two studies, we measured the horizontal movements of the eyes (using mobile eye tracking in Studies 1 and 2) and the head (using inertial sensors in Study 2) while participants completed a walking task and a search and retrieval task in a large, outdoor environment. We found that the spread of visual exploration was greater while searching compared with walking, and this was primarily driven by increased movement of the head as opposed to the eyes. The contributions of the head to gaze shifts of different eccentricities was greater when searching compared to when walking. Findings are discussed with respect to understanding visual exploration as a motor action with multiple degrees of freedom.
- Published
- 2021
10. Spontaneous head movements support accurate horizontal auditory localization in a virtual visual environment.
- Author
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Gulli A, Fontana F, Orzan E, Aruffo A, and Muzzi E
- Subjects
- Child, Humans, Head Movements, Sound Localization
- Abstract
This study investigates the relationship between auditory localization accuracy in the horizontal plane and the spontaneous translation and rotation of the head in response to an acoustic stimulus from an invisible sound source. Although a number of studies have suggested that localization ability improves with head movements, most of them measured the perceived source elevation and front-back disambiguation. We investigated the contribution of head movements to auditory localization in the anterior horizontal field in normal hearing subjects. A virtual reality scenario was used to conceal visual cues during the test through a head mounted display. In this condition, we found that an active search of the sound origin using head movements is not strictly necessary, yet sufficient for achieving greater sound source localization accuracy. This result may have important implications in the clinical assessment and training of adults and children affected by hearing and motor impairments., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2022 Gulli et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
- Published
- 2022
- Full Text
- View/download PDF
11. Efficient training approaches for optimizing behavioral performance and reducing head fixation time.
- Author
-
Nasr A, Dominiak SE, Sehara K, Nashaat MA, Sachdev RNS, and Larkum ME
- Subjects
- Mice, Animals, Behavior, Animal, Head Movements, Learning
- Abstract
The use of head fixation has become routine in systems neuroscience. However, whether the behavior changes with head fixation, whether animals can learn aspects of a task while freely moving and transfer this knowledge to the head fixed condition, has not been examined in much detail. Here, we used a novel floating platform, the "Air-Track", which simulates free movement in a real-world environment to address the effect of head fixation and developed methods to accelerate training of behavioral tasks for head fixed mice. We trained mice in a Y maze two choice discrimination task. One group was trained while head fixed and compared to a separate group that was pre-trained while freely moving and then trained on the same task while head fixed. Pre-training significantly reduced the time needed to relearn the discrimination task while head fixed. Freely moving and head fixed mice displayed similar behavioral patterns, however, head fixation significantly slowed movement speed. The speed of movement in the head fixed mice depended on the weight of the platform. We conclude that home-cage pre-training improves learning performance of head fixed mice and that while head fixation obviously limits some aspects of movement, the patterns of behavior observed in head fixed and freely moving mice are similar., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2022 Nasr et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
- Published
- 2022
- Full Text
- View/download PDF
12. Dynamic arm movements attenuate the perceptual distortion of visual vertical induced during prolonged whole-body tilt
- Author
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Keisuke Tani, Yasushi Kodaka, Keisuke Kushiro, and Shinji Yamamoto
- Subjects
Male ,Central Nervous System ,Vision ,Physiology ,Sensory Physiology ,Social Sciences ,Statics ,Somatosensory system ,Nervous System ,Medicine and Health Sciences ,Psychology ,Perceptual Distortion ,Mathematics::Representation Theory ,media_common ,Multidisciplinary ,Physics ,Classical Mechanics ,Sensory Systems ,Arms ,Tilt (optics) ,Somatosensory System ,Head Movements ,Shutters ,Physical Sciences ,Arm ,Visual Perception ,Medicine ,Engineering and Technology ,Female ,Sensory Perception ,Anatomy ,Whole body ,Gravitation ,Research Article ,Adult ,medicine.medical_specialty ,Science ,media_common.quotation_subject ,Movement ,Posture ,Young Adult ,Physical medicine and rehabilitation ,Perception ,Orientation ,medicine ,Humans ,Mechanical Engineering ,Cognitive Psychology ,Biology and Life Sciences ,Space Perception ,Body Limbs ,Cognitive Science ,Neuroscience - Abstract
Concurrent body movements have been shown to enhance the accuracy of spatial judgment, but it remains unclear whether they also contribute to perceptual estimates of gravitational space not involving body movements. To address this, we evaluated the effects of static or dynamic arm movements during prolonged whole-body tilt on the subsequent perceptual estimates of visual or postural vertical. In Experiment 1, participants were asked to continuously perform static or dynamic arm movements during prolonged tilt, and we assessed their effects on the prolonged tilt-induced shifts of subjective visual vertical (SVV) at a tilted position (during-tiltsession) or near upright (post-tiltsession). In Experiment 2, we evaluated how static or dynamic arm movements during prolonged tilt subsequently affected the subjective postural vertical (SPV). In Experiment 1, we observed that the SVV was significantly shifted toward the direction of prolonged tilt in both sessions. The SVV shifts decreased when performing dynamic arm movements in theduring-tiltsession, but not in thepost-tiltsession. In Experiment 2, as well as SVV, the SPV was shifted toward the direction of prolonged tilt, but it was not significantly attenuated by the performance of static or dynamic arm movements. The results of theduring-tiltsession suggest that the central nervous system utilizes additional information generated by dynamic body movements for perceptual estimates of visual vertical.
- Published
- 2020
13. Pseudo-spontaneous nystagmus in lateral semicircular canal benign paroxysmal positional vertigo: Correlation with bow and lean test in a pitch plane
- Author
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Dong Gu Hur, Hyun-Jin Lee, Seong Ki Ahn, Chae Dong Yim, and Dae Hwan Kim
- Subjects
Male ,genetic structures ,Epidemiology ,Labyrinth Diseases ,Otology ,Nystagmus ,Lithiasis ,Otolith ,Correlation ,Vertigo ,Medicine and Health Sciences ,Outpatient clinic ,Benign Paroxysmal Positional Vertigo ,Sitting Position ,Multidisciplinary ,biology ,Middle Aged ,Head Movements ,Inner Ear ,Medicine ,Lateral semicircular canal ,Female ,medicine.symptom ,Anatomy ,Research Article ,Adult ,medicine.medical_specialty ,Benign paroxysmal positional vertigo ,Science ,Posture ,Nystagmus, Pathologic ,Signs and Symptoms ,Ophthalmology ,medicine ,Humans ,In patient ,Spontaneous nystagmus ,Outpatient Clinics ,Aged ,business.industry ,Biology and Life Sciences ,medicine.disease ,biology.organism_classification ,Semicircular Canals ,Health Care ,Otorhinolaryngology ,Ears ,Health Care Facilities ,Lesions ,Clinical Medicine ,business ,Head - Abstract
Objectives We investigated the incidence and characteristics of pseudo-spontaneous nystagmus (PSN) in benign paroxysmal positional vertigo involving the lateral semicircular canal (LC-BPPV) and evaluated the correlation between PSN and the bow and lean test. Methods We examined nystagmus in the sitting position using video-oculography goggles in 131 LC-BPPV patients. The positioning test and bow and lean test were also performed. Patients were divided into canalolithiasis and cupulolithiasis groups according to the character of nystagmus. In each group, the incidence and direction of PSN, correlation with the bow and lean test, and treatment outcome were analyzed. Results PSN was observed in 25 cases (19.1%) in LC-BPPV patients, 7 of which were canalolithiasis and 18 of which were cupulolithiasis (p = 0.098). Of the 25 patients with PSN, 21 (84%) exhibited nystagmus consistent with the lean test whereas 4 (16%) exhibited nystagmus consistent with the bow test. In patients with PSN, nystagmus was observed in the bow and lean test in all cases (23/23), but in patients without PSN, no nystagmus was observed in 13 cases (13/87) in the bow and lean test (p = 0.048). The number of barbecue maneuvers performed until the end of treatment was 1.4 ± 0.7 in patients with PSN and 1.4 ± 0.9 in those without PSN (p = 0.976). Conclusion We identified PSN in patients with LC-BPPV irrelevant of subtype. Moreover, all patients with PSN showed nystagmus in the bow and lean test. The direction of PSN was mostly consistent with that of the lean test (21/25, 84%). The presence of PSN was not related to the treatment outcome in this study.
- Published
- 2020
14. Locomotor illusions are generated by perceptual body-environment organization
- Author
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Martin Dobricki, David Weibel, Leonardo Angelini, Elena Mugellini, and Fred W Mast
- Subjects
Male ,Adolescent ,Psychometrics ,Physiology ,Vision ,Science ,Motion Perception ,Vibration Engineering ,Social Sciences ,Walking ,Vibration ,Young Adult ,Physical Stimulation ,Body Image ,Medicine and Health Sciences ,Humans ,Psychology ,Gait ,Biological Locomotion ,Feet ,musculoskeletal, neural, and ocular physiology ,Mechanical Engineering ,Physics ,Virtual Reality ,Cognitive Psychology ,Biology and Life Sciences ,Classical Mechanics ,Proprioception ,Illusions ,Head Movements ,Space Perception ,Body Limbs ,Physical Sciences ,Medicine ,Cognitive Science ,Legs ,Engineering and Technology ,Female ,Perception ,Sensory Perception ,Anatomy ,150 Psychology ,Locomotion ,Photic Stimulation ,Research Article ,Neuroscience - Abstract
While one is walking, the stimulation by one's body forms a structure with the stimulation by the environment. This locomotor array of stimulation corresponds to the human-environment relation that one's body forms with the environment it is moving through. Thus, the perceptual experience of walking may arise from such a locomotor array of stimulation. Humans can also experience walking while they are sitting. In this case, there is no stimulation by one's walking body. Hence, one can experience walking although a basic component of a locomotor array of stimulation is missing. This may be facilitated by perception organizing the sensory input about one's body and environment into a perceptual structure that corresponds to a locomotor array of stimulation. We examined whether locomotor illusions are generated by this perceptual formation of a locomotor structure. We exposed sixteen seated individuals to environmental stimuli that elicited either the perceptual formation of a locomotor structure or that of a control structure. The study participants experienced distinct locomotor illusions when they were presented with environmental stimuli that elicited the perceptual formation of a locomotor structure. They did not experience distinct locomotor illusions when the stimuli instead elicited the perceptual formation of the control structure. These findings suggest that locomotor illusions are generated by the perceptual organization of sensory input about one's body and environment into a locomotor structure. This perceptual body-environment organization elucidates why seated human individuals experience the sensation of walking without any proprioceptive or kinaesthetic stimulation.
- Published
- 2020
15. Eye-head coordination and dynamic visual scanning as indicators of visuo-cognitive demands in driving simulator
- Author
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Delphine Bernardin, Sergio Mejia-Romero, Amigale Patoine, Jocelyn Faubert, Romain Chaumillon, Eduardo Lugo, and Laura Mikula
- Subjects
Male ,Eye Movements ,genetic structures ,Vision ,Physiology ,Visual System ,Computer science ,Entropy ,Sensory Physiology ,Visual Acuity ,Social Sciences ,Emmetropia ,Cognition ,0302 clinical medicine ,Medicine and Health Sciences ,Psychology ,Attention ,Eye Lens ,Multidisciplinary ,Physics ,05 social sciences ,Driving simulator ,Sensory Systems ,Head Movements ,Physical Sciences ,Thermodynamics ,Medicine ,Female ,Sensory Perception ,Anatomy ,Research Article ,Cognitive psychology ,Adult ,Automobile Driving ,Ocular Anatomy ,Science ,050105 experimental psychology ,03 medical and health sciences ,Risk-Taking ,Ocular System ,Humans ,0501 psychology and cognitive sciences ,Simulation Training ,Vision, Ocular ,Visual search ,Behavior ,Cognitive Psychology ,Biology and Life Sciences ,Eye movement ,Gaze ,eye diseases ,Cognitive Science ,Eyes ,Perception ,Head ,Psychomotor Performance ,030217 neurology & neurosurgery ,Neuroscience - Abstract
Driving is an everyday task involving a complex interaction between visual and cognitive processes. As such, an increase in the cognitive and/or visual demands can lead to a mental overload which can be detrimental for driving safety. Compiling evidence suggest that eye and head movements are relevant indicators of visuo-cognitive demands and attention allocation. This study aims to investigate the effects of visual degradation on eye-head coordination as well as visual scanning behavior during a highly demanding task in a driving simulator. A total of 21 emmetropic participants (21 to 34 years old) performed dual-task driving in which they were asked to maintain a constant speed on a highway while completing a visual search and detection task on a navigation device. Participants did the experiment with optimal vision and with contact lenses that introduced a visual perturbation (myopic defocus). The results indicate modifications of eye-head coordination and the dynamics of visual scanning in response to the visual perturbation induced. More specifically, the head was more involved in horizontal gaze shifts when the visual needs were not met. Furthermore, the evaluation of visual scanning dynamics, based on time-based entropy which measures the complexity and randomness of scanpaths, revealed that eye and gaze movements became less explorative and more stereotyped when vision was not optimal. These results provide evidence for a reorganization of both eye and head movements in response to increasing visual-cognitive demands during a driving task. Altogether, these findings suggest that eye and head movements can provide relevant information about visuo-cognitive demands associated with complex tasks. Ultimately, eye-head coordination and visual scanning dynamics may be good candidates to estimate drivers’ workload and better characterize risky driving behavior.
- Published
- 2020
16. Effects of driver compensatory behaviour on risks of critical pedestrian collisions under simulated visual field defects
- Author
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Makoto Itoh and Jieun Lee
- Subjects
Male ,Time Factors ,Eye Movements ,genetic structures ,Vision ,Epidemiology ,Physiology ,Visual System ,Computer science ,Sensory Physiology ,Social Sciences ,Advanced driver assistance systems ,Kaplan-Meier Estimate ,Compensation (engineering) ,0302 clinical medicine ,Medicine and Health Sciences ,Psychology ,Public and Occupational Health ,media_common ,Visual Impairments ,Multidisciplinary ,Traumatic Injury Risk Factors ,Accidents, Traffic ,Driving simulator ,Sensory Systems ,Visual field ,Road Traffic Collisions ,Head Movements ,Engineering and Technology ,Medicine ,Sensory Perception ,Female ,Safety ,medicine.symptom ,Research Article ,Adult ,Automobile Driving ,medicine.medical_specialty ,media_common.quotation_subject ,Science ,Visual impairment ,Pedestrian ,Young Adult ,03 medical and health sciences ,Physical medicine and rehabilitation ,Perception ,medicine ,Humans ,Computer Simulation ,Pedestrians ,Behavior ,Mechanical Engineering ,Traffic Safety ,Biology and Life Sciences ,Ophthalmology ,Medical Risk Factors ,Automotive Engineering ,030221 ophthalmology & optometry ,Brakes ,Visual Fields ,human activities ,030217 neurology & neurosurgery ,Neuroscience - Abstract
Compensatory behaviour is regarded as a helpful strategy to mediate drivers' deteriorated hazard perception ability due to visual field defects. However, helpfulness of compensatory behaviour for drivers with advanced visual field defects has largely unexplored. This study aims to clarify the effectiveness and limitation of compensatory head movements in critical situations where included pedestrians stepping off a sidewalk under the simulation of advanced visual defects. 18 healthy-sighted drivers participated the data collection that was conducted in a driving simulator under three driving conditions: (1) without visual impairment, (2) with visual impairment and not performing active compensation, and (3) with visual impairment but performing active compensation. The result showed that active compensation led quick accelerator and brake response times, reducing the risk and number of pedestrian collisions. The active compensation led a decrease in the number of non-responses to hazardous pedestrians compared to while driving not performing compensation. However, the compensation could not reduce the number of pedestrian collisions to those of healthy-sighted drivers. Compensatory viewing behaviour contributed to improved driving performance as well as has limits to lead driving performance like healthy-sighted drivers. Developing driver assistance systems and practical compensatory strategies concerning the degrees of impairment and traffic conditions may provide opportunities to improve driving safety deteriorated hazard perception for visually impaired drivers.
- Published
- 2020
17. Cerebellum-mediated trainability of eye and head movements for dynamic gazing
- Author
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Koichi Hosomi, Naoki Yoshida, Youichi Saitoh, Akiyoshi Matsugi, Satoru Nishishita, Shinya Douchi, Nobuhiko Mori, Kosuke Oku, and Yohei Okada
- Subjects
Male ,Cerebellum ,genetic structures ,Eye Movements ,Physiology ,Visual System ,Vision ,medicine.medical_treatment ,Sensory Physiology ,Social Sciences ,0302 clinical medicine ,Mathematical and Statistical Techniques ,Reflexes ,Medicine and Health Sciences ,Psychology ,Cerebral Cortex ,0303 health sciences ,Brain Mapping ,Multidisciplinary ,medicine.diagnostic_test ,Statistics ,Brain ,Eukaryota ,Electrooculography ,Transcranial Magnetic Stimulation ,Sensory Systems ,Healthy Volunteers ,Electrophysiology ,Insects ,medicine.anatomical_structure ,Bioassays and Physiological Analysis ,Brain Electrophysiology ,Moths and Butterflies ,Head Movements ,Physical Sciences ,Medicine ,Sensory Perception ,Female ,Anatomy ,Research Article ,medicine.medical_specialty ,Arthropoda ,Science ,Neurophysiology ,Fixation, Ocular ,Research and Analysis Methods ,03 medical and health sciences ,Young Adult ,Physical medicine and rehabilitation ,Ocular System ,medicine ,Functional electrical stimulation ,Animals ,Humans ,Statistical Methods ,Transcranial Stimulation ,030304 developmental biology ,Analysis of Variance ,business.industry ,Electrophysiological Techniques ,Organisms ,Eye movement ,Biology and Life Sciences ,Bayes Theorem ,Gaze ,Invertebrates ,Transcranial magnetic stimulation ,Fixation (visual) ,Reflex ,Eyes ,sense organs ,business ,Head ,030217 neurology & neurosurgery ,Mathematics ,Neuroscience - Abstract
Objective To investigate whether gaze stabilization exercises (GSEs) improve eye and head movements and whether low-frequency cerebellar repetitive transcranial magnetic stimulation (rTMS) inhibits GSE trainability. Methods 25 healthy adults (real rTMS, n = 12; sham rTMS, n = 13) were recruited. Real or sham rTMS was performed for 15 min (1 Hz, 900 stimulations). The center of the butterfly coil was set 1 cm below the inion in the real rTMS. Following stimulation, 10 trials of 1 min of a GSE were conducted at 1 min intervals. In the GSE, the subjects were instructed to stand upright and horizontally rotate their heads according to a beeping sound corresponding to 2 Hz and with a gaze point ahead of them. Electrooculograms were used to estimate the horizontal gaze direction of the right eye, and gyroscopic measurements were performed to estimate the horizontal head angular velocity during the GSE trials. The percentage change from the first trial of motion range of the eye and head was calculated for each measurement. The percent change of the eye/head range ratio was calculated to assess the synchronous changes of the eye and head movements as the exercise increased. Results Bayesian two-way analysis of variance showed that cerebellar rTMS affected the eye motion range and eye/head range ratio. A post hoc comparison (Bayesian t-test) showed evidence that the eye motion range and eye/head range ratio were reduced in the fifth, sixth, and seventh trials compared with the first trial sham stimulation condition. Conclusions GSEs can modulate eye movements with respect to head movements, and the cerebellum may be associated with eye-head coordination trainability for dynamic gazing during head movements.
- Published
- 2019
18. A question of (perfect) timing: A preceding head turn increases the head-fake effect in basketball
- Author
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Iris Güldenpenning, Matthias Weigelt, and Andrea Polzien
- Subjects
Male ,Head (linguistics) ,Social Sciences ,ComputingMilieux_LEGALASPECTSOFCOMPUTING ,Mathematical and Statistical Techniques ,0302 clinical medicine ,Medicine and Health Sciences ,Psychology ,Multidisciplinary ,05 social sciences ,Brain ,Anticipation ,Sports Science ,Curve Fitting ,Head Movements ,Medicine ,Sensory Perception ,Anatomy ,Sports ,Research Article ,Cognitive psychology ,Deception ,Basketball ,Science ,Cognitive Neuroscience ,Ocular Anatomy ,Prefrontal Cortex ,Athletic Performance ,Research and Analysis Methods ,GeneralLiterature_MISCELLANEOUS ,050105 experimental psychology ,03 medical and health sciences ,Sensory Cues ,Ocular System ,Reaction Time ,Humans ,0501 psychology and cognitive sciences ,Sensory cue ,Practical implications ,Behavior ,Cognitive Psychology ,Biology and Life Sciences ,Pupil ,Stimulus onset asynchrony ,Action (philosophy) ,Recreation ,Cognitive Science ,Eyes ,ComputingMilieux_COMPUTERSANDSOCIETY ,Perception ,Head ,Mathematical Functions ,030217 neurology & neurosurgery ,Neuroscience - Abstract
In many kinds of sports, deceptive actions are frequently used to hamper the anticipation of an opponent. The head fake in basketball is often applied to deceive an observer regarding the direction of a pass. To perform a head fake, a basketball player turns the head in one direction, but passes the ball to the opposite direction. Several studies showed that reactions to passes with head fakes are slower and more error-prone than to passes without head fakes (head-fake effect). The aim of a basketball player is to produce a head-fake effect for as large as possible in the opponent. The question if the timing of the deceptive action influences the size of the head-fake effect has not yet been examined systematically. The present study investigated if the head-fake effect depends on the temporal lag between the head turn and the passing movement. To this end, the stimulus onset asynchrony between head turn, and pass was varied between 0 and 800 ms. The results showed the largest effect when the head turn precedes the pass by 300 ms. This result can be explained better by facilitating the processing of passes without head fake than by making it more difficult to process passes with a head fake. This result is discussed regarding practical implications and conclusions about the underlying mechanism of the head–fake effect in basketball are drawn.
- Published
- 2021
19. The combined effect of eye movements improve head centred local motion information during walking
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Szonya Durant and Johannes M. Zanker
- Subjects
genetic structures ,Eye Movements ,Head (linguistics) ,Computer science ,Physiology ,Visual System ,Vision ,Computer Vision ,Sensory Physiology ,Motion Perception ,Social Sciences ,Pilot Projects ,Walking ,Signal ,Motion (physics) ,chemistry.chemical_compound ,0302 clinical medicine ,Medicine and Health Sciences ,Drosophila Proteins ,Psychology ,Computer vision ,Multidisciplinary ,05 social sciences ,Cameras ,Sensory Systems ,DNA-Binding Proteins ,medicine.anatomical_structure ,Optical Equipment ,Head Movements ,Medicine ,Engineering and Technology ,Sensory Perception ,Anatomy ,Research Article ,Computer and Information Sciences ,Science ,Ocular Anatomy ,Equipment ,Optic Flow ,050105 experimental psychology ,Retina ,03 medical and health sciences ,Ocular System ,medicine ,Humans ,0501 psychology and cognitive sciences ,Motion perception ,business.industry ,Biological Locomotion ,Eye movement ,Biology and Life Sciences ,Retinal ,Gaze ,eye diseases ,Target Detection ,chemistry ,Eye tracking ,Eyes ,Smart Glasses ,Artificial intelligence ,Noise (video) ,sense organs ,business ,Head ,030217 neurology & neurosurgery ,Photic Stimulation ,Neuroscience - Abstract
Eye movements play multiple roles in human behaviour-small stabilizing movements are important for keeping the image of the scene steady during locomotion, whilst large scanning movements search for relevant information. It has been proposed that eye movement induced retinal motion interferes with the estimation of self-motion based on optic flow. We investigated the effect of eye movements on retinal motion information during walking. Observers walked towards a target, wearing eye tracking glasses that simultaneously recorded the scene ahead and tracked the movements of both eyes. By realigning the frames of the recording from the scene ahead, relative to the centre of gaze, we could mimic the input received by the retina (retinocentric coordinates) and compare this to the input received by the scene camera (head centred coordinates). We asked which of these coordinate frames resulted in the least noisy motion information. Motion noise was calculated by finding the error in between the optic flow signal and a noise-free motion expansion pattern. We found that eye movements improved the optic flow information available, even when large diversions away from target were made.
- Published
- 2019
20. Head-neck rotational movements using DidRen laser test indicate children and seniors' lower performance
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Jean-Michel Brismée, Christine Detrembleur, Laurent Pitance, Fabien Buisseret, Frédéric Dierick, Renaud Hage, UCL - SSS/IREC/NMSK - Neuro-musculo-skeletal Lab, and UCL - (SLuc) Service de stomatologie et de chirurgie maxillo-faciale
- Subjects
Male ,Kinematics ,Vision ,Developmental approach ,Deceleration ,neck pain ,Social Sciences ,Audiology ,0302 clinical medicine ,Elderly ,Reflexes ,Medicine and Health Sciences ,Psychology ,Sensorimotor control ,Child ,Aged, 80 and over ,030222 orthopedics ,Multidisciplinary ,DidRen laser test ,Physics ,Classical Mechanics ,Middle Aged ,Biomechanical Phenomena ,Optical Equipment ,Head Movements ,Physical Sciences ,Engineering and Technology ,Medicine ,Sensory Perception ,Female ,medicine.symptom ,Anatomy ,Rotational dynamics ,Research Article ,Adult ,medicine.medical_specialty ,Adolescent ,Rotation ,Science ,Acceleration ,Equipment ,Axial rotation ,Execution time ,Asymptomatic ,03 medical and health sciences ,Young Adult ,medicine ,Humans ,Aged ,business.industry ,Lasers ,Head neck ,Biology and Life Sciences ,Younger adults ,Age Groups ,People and Places ,Population Groupings ,business ,Head ,030217 neurology & neurosurgery ,Neck ,Neuroscience - Abstract
Sensorimotor control strategies during cervical axial rotation movements have been previously explored in narrow age ranges but never concurrently in Children and Seniors during a well-standardized task. However, the lifespan developmental approach provides a framework for research in human sensorimotor control of the head-neck complex. A cross-sectional design was used to investigate the influence of age on head-neck dynamic performance adopted by asymptomatic Children, Adults and Seniors using a standardized task (DidRen Laser test). Participants performed 5 cycles of left/right head-neck complex fast rotational movements toward 3 targets with 30° of angular separation. Dynamic performances were computed from total execution time of the test and kinematic variables derived from rotational motion of head measured by an optoelectronic system. Eighty-one participants, aged 8–85 yrs, were stratified in four groups: Children, Younger adults, Older adults and Seniors. Children were significantly slower than Younger (p
- Published
- 2019
21. Getting the nod: Pediatric head motion in a transdiagnostic sample during movie- and resting-state fMRI.
- Author
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Frew S, Samara A, Shearer H, Eilbott J, and Vanderwal T
- Subjects
- Adolescent, Adult, Artifacts, Brain diagnostic imaging, Child, Child, Preschool, Female, Head Movements, Humans, Male, Motion, Rotation, Young Adult, Magnetic Resonance Imaging, Motion Pictures
- Abstract
Head motion continues to be a major problem in fMRI research, particularly in developmental studies where an inverse relationship exists between head motion and age. Despite multifaceted and costly efforts to mitigate motion and motion-related signal artifact, few studies have characterized in-scanner head motion itself. This study leverages a large transdiagnostic public dataset (N = 1388, age 5-21y, The Healthy Brain Network Biobank) to characterize pediatric head motion in space, frequency, and time. We focus on practical aspects of head motion that could impact future study design, including comparing motion across groups (low, medium, and high movers), across conditions (movie-watching and rest), and between males and females. Analyses showed that in all conditions, high movers exhibited a different pattern of motion than low and medium movers that was dominated by x-rotation, and z- and y-translation. High motion spikes (>0.3mm) from all participants also showed this pitch-z-y pattern. Problematic head motion is thus composed of a single type of biomechanical motion, which we infer to be a nodding movement, providing a focused target for motion reduction strategies. A second type of motion was evident via spectral analysis of raw displacement data. This was observed in low and medium movers and was consistent with respiration rates. We consider this to be a baseline of motion best targeted in data preprocessing. Further, we found that males moved more than, but not differently from, females. Significant cross-condition differences in head motion were found. Movies had lower mean motion, and especially in high movers, movie-watching reduced within-run linear increases in head motion (i.e., temporal drift). Finally, we used intersubject correlations of framewise displacement (FD-ISCs) to assess for stimulus-correlated motion trends. Subject motion was more correlated in movie than rest, and 8 out of top 10 FD-ISC windows had FD below the mean. Possible reasons and future implications of these findings are discussed., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2022
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22. Joint and individual effectiveness of galvanic cutaneous stimulation and tactile stimulation at decreasing Simulator Adaptation Syndrome
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Fernando Elias Martins Fonseca, Javier Albayay, Germán Gálvez-García, and Claudio Bascour-Sandoval
- Subjects
Male ,Vision ,Social Sciences ,Stimulation ,0302 clinical medicine ,Distraction ,Medicine and Health Sciences ,Psychology ,Medicine ,Mastoid Process ,Attention ,Musculoskeletal System ,Fatigue ,050107 human factors ,Multidisciplinary ,Sensory stimulation therapy ,Physics ,05 social sciences ,Classical Mechanics ,Galvanic Skin Response ,Adaptation, Physiological ,Navigation ,Treatment Outcome ,Head Movements ,Physical Sciences ,Transcutaneous Electric Nerve Stimulation ,Simulator sickness ,Engineering and Technology ,Head movements ,Steering ,Sensory Perception ,Female ,Anatomy ,Research Article ,Cutaneous stimulation ,Adult ,Automobile Driving ,Adolescent ,Motion Sickness ,Science ,Cognitive Neuroscience ,Surgical and Invasive Medical Procedures ,Adaptation (eye) ,Vibration ,Motor Reactions ,Young Adult ,03 medical and health sciences ,Signs and Symptoms ,Humans ,Functional electrical stimulation ,0501 psychology and cognitive sciences ,Skeleton ,Simulation ,Functional Electrical Stimulation ,business.industry ,Skull ,Cognitive Psychology ,Biology and Life Sciences ,Postural Control ,High Fidelity Simulation Training ,Touch ,Cognitive Science ,Perception ,Clinical Medicine ,business ,030217 neurology & neurosurgery ,Neuroscience - Abstract
This research was focused on investigating the effectiveness of galvanic cutaneous stimulation and tactile stimulation jointly and individually at mitigating Simulator Adaptation Syndrome. Forty drivers (mean age = 23.1 ± 3.4 years old, twenty women) participated in a driving simulation experiment. Total scores of the Simulator Sickness Questionnaire, head movements (an index of body balance), and driving performance variables were compared across four different stimulation conditions: i) baseline (where no stimulation was presented), ii) galvanic cutaneous stimulation and iii) tactile stimulation deployed individually, and iv) both techniques deployed jointly. The results showed that both techniques presented in conjunction alleviate Simulator Adaptation Syndrome and improve driving performance more effectively than when they are presented in isolation. Importantly, reduced head movements were only revealed when galvanic cutaneous stimulation was applied. We concluded that the reduction of this syndrome is due to an improvement of body balance (elicited by galvanic cutaneous stimulation), and a distraction from the symptoms (elicited by tactile stimulation). We encourage the use of both techniques simultaneously to decrease Simulator Adaptation Syndrome.
- Published
- 2020
23. Markerless motion tracking and correction for PET, MRI, and simultaneous PET/MRI
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Oline Vinter Olesen, Ian Law, Andreas H Ellegaard, Stefan L. Glimberg, Jakob Mølkjær Slipsager, Rasmus Reinhold Paulsen, Lisbeth Marner, Otto M. Henriksen, M. Dylan Tisdall, Paul Wighton, and Andre van der Kouwe
- Subjects
Computer science ,Science ,Standardized uptake value ,Tracking (particle physics) ,Multimodal Imaging ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,Motion ,0302 clinical medicine ,Match moving ,Neuroimaging ,Neoplasms ,medicine ,Image Processing, Computer-Assisted ,Humans ,Prospective Studies ,Child ,Multidisciplinary ,medicine.diagnostic_test ,Brain ,Reproducibility of Results ,Magnetic resonance imaging ,Magnetic Resonance Imaging ,Positron emission tomography ,Head Movements ,Positron-Emission Tomography ,Medicine ,030217 neurology & neurosurgery ,Biomedical engineering - Abstract
ObjectiveWe demonstrate and evaluate the first markerless motion tracker compatible with PET, MRI, and simultaneous PET/MRI systems for motion correction (MC) of brain imaging.MethodsPET and MRI compatibility is achieved by careful positioning of in-bore vision extenders and by placing all electronic components out-of-bore. The motion tracker is demonstrated in a clinical setup during a pediatric PET/MRI study including 94 pediatric patient scans. PET MC is presented for two of these scans using a customized version of the Multiple Acquisition Frame method. Prospective MC of MRI acquisition of two healthy subjects is demonstrated using a motion-aware MRI sequence. Real-time motion estimates are accompanied with a tracking validity parameter to improve tracking reliability.ResultsFor both modalities, MC shows that motion induced artifacts are noticeably reduced and that motion estimates are sufficiently accurate to capture motion ranging from small respiratory motion to large intentional motion. In the PET/MRI study, a time-activity curve analysis shows image improvements for a patient performing head movements corresponding to a tumor motion of ±5-10 mm with a 19% maximal difference in standardized uptake value before and after MC.ConclusionThe first markerless motion tracker is successfully demonstrated for prospective MC in MRI and MC in PET with good tracking validity.SignificanceAs simultaneous PET/MRI systems have become available for clinical use, an increasing demand for accurate motion tracking and MC in PET/MRI scans has emerged. The presented markerless motion tracker facilitate this demand.
- Published
- 2018
24. Optimization based trajectory planning for real-time 6DoF robotic patient motion compensation systems
- Author
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Rodney D. Wiersma and Xinmin Liu
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Male ,Computer science ,Cancer Treatment ,PID controller ,030218 nuclear medicine & medical imaging ,0302 clinical medicine ,Robotic Surgical Procedures ,Medicine and Health Sciences ,Multidisciplinary ,Phantoms, Imaging ,Physics ,Classical Mechanics ,Robotics ,Trajectory optimization ,Oncology ,030220 oncology & carcinogenesis ,Head Movements ,Physical Sciences ,Trajectory ,Medicine ,Engineering and Technology ,Robots ,Research Article ,Clinical Oncology ,Optimization ,Science ,Radiation Therapy ,Radiosurgery ,Patient Positioning ,03 medical and health sciences ,Acceleration ,Motion ,Control theory ,Computer Systems ,Robotics Systems ,Humans ,Computer Simulation ,Motion planning ,Motion compensation ,business.industry ,Radiotherapy Planning, Computer-Assisted ,Mechanical Engineering ,Prostatic Neoplasms ,Control system ,Robot ,Artificial intelligence ,Clinical Medicine ,business ,Actuator ,Beam (structure) ,Actuators ,Mathematics - Abstract
PurposeRobotic stabilization of a therapeutic radiation beam with respect to a dynamically moving tumor target can be accomplished either by moving the radiation source, the patient, or both. As the treatment beam is on during this process, the primary goal is to minimize exposure of normal tissue to radiation as much as possible when moving the target back to the desired position. Due to the complex mechanical structure of 6 degree-of-freedom (6DoF) robots, it is not intuitive as to what 6 dimensional (6D) correction trajectory is optimal in achieving such a goal. With proportional-integrative-derivative (PID) and other controls, the potential exists that the controller may generate a trajectory that is highly curved, slow, or suboptimal in that it leads to unnecessary exposure of healthy tissue to radiation. This work investigates a novel feedback planning method that takes into account a robot's mechanical joint structure, patient safety tolerances, and other system constraints, and performs real-time optimization to search the entire 6D trajectory space in each time cycle so it can respond with an optimal 6D correction trajectory.MethodsComputer simulations were created for two 6DoF robotic patient support systems: a Stewart-Gough platform for moving a patient's head in frameless maskless stereotactic radiosurgery, and a linear accelerator treatment table for moving a patient in prostate cancer radiation therapy. Motion planning was formulated as an optimization problem and solved at real-time speeds using the L-BFGS algorithm. Three planning methods were investigated, moving the platform as fast as possible (platform-D), moving the target along a straight-line (target-S), and moving the target based on the fastest descent of position error (target-D). Both synthetic motion and prior recorded human motion were used as input data and output results were analyzed.ResultsFor randomly generated 6D step-like and sinusoidal synthetic input motion, target-D planning demonstrated the smallest net trajectory error in all cases. On average, optimal planning was found to have a 45% smaller target trajectory error than platform-D control, and a 44% smaller target trajectory error than target-S planning. For patient head motion compensation, only target-D planning was able to maintain a ≤0.5mm and ≤0.5deg clinical tolerance objective for 100% of the treatment time. For prostate motion, both target-S planning and target-D planning outperformed platform-D control.ConclusionsA general 6D target trajectory optimization framework for robotic patient motion compensation systems was investigated. The method was found to be flexible as it allows control over various performance requirements such as mechanical limits, velocities, acceleration, or other system control objectives.
- Published
- 2018
25. Influence of seating styles on head and pelvic vertical movement symmetry in horses ridden at trot
- Author
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Persson-Sjodin, Emma, Hernlund, Elin, Pfau, Thilo, Haubro Andersen, Pia, and Rhodin, Marie
- Subjects
Male ,Inertia ,Lameness, Animal ,lcsh:Medicine ,Geographical locations ,Weight-Bearing ,Forelimb ,Medicine and Health Sciences ,lcsh:Science ,Musculoskeletal System ,Instrumentation ,Gait ,Mammals ,Data Processing ,Physics ,Eukaryota ,Classical Mechanics ,Biomechanical Phenomena ,Hindlimb ,Europe ,Research Design ,Head Movements ,Vertebrates ,Physical Sciences ,Engineering and Technology ,Female ,Anatomy ,Information Technology ,Research Article ,Computer and Information Sciences ,Movement ,Equines ,Posture ,Research and Analysis Methods ,Pelvis ,Motion ,Animals ,Horses ,European Union ,Retrospective Studies ,Sweden ,lcsh:R ,Organisms ,Biology and Life Sciences ,Amniotes ,Exercise Test ,lcsh:Q ,People and places ,Electronics ,Accelerometers ,Head - Abstract
Detailed knowledge of how a rider's seating style and riding on a circle influences the movement symmetry of the horse's head and pelvis may aid rider and trainer in an early recognition of low grade lameness. Such knowledge is also important during both subjective and objective lameness evaluations in the ridden horse in a clinical setting. In this study, inertial sensors were used to assess how different rider seating styles may influence head and pelvic movement symmetry in horses trotting in a straight line and on the circle in both directions. A total of 26 horses were subjected to 15 different conditions at trot: three unridden conditions and 12 ridden conditions where the rider performed three different seating styles (rising trot, sitting trot and two point seat). Rising trot induced systematic changes in movement symmetry of the horses. The most prominent effect was decreased pelvic rise that occurred as the rider was actively rising up in the stirrups, thus creating a downward momentum counteracting the horses push off. This mimics a push off lameness in the hindlimb that is in stance when the rider sits down in the saddle during the rising trot. On the circle, the asymmetries induced by rising trot on the correct diagonal counteracted the circle induced asymmetries, rendering the horse more symmetrical. This finding offers an explanation to the equestrian tradition of rising on the 'correct diagonal.' In horses with small pre-existing movement asymmetries, the asymmetry induced by rising trot, as well as the circular track, attenuated or reduced the horse's baseline asymmetry, depending on the sitting diagonal and direction on the circle. A push off hindlimb lameness would be expected to increase when the rider sits during the lame hindlimb stance whereas an impact hindlimb lameness would be expected to decrease. These findings suggest that the rising trot may be useful for identifying the type of lameness during subjective lameness assessment of hindlimb lameness. This theory needs to be studied further in clinically lame horses.
- Published
- 2018
26. European starlings use their acute vision to check on feline predators but not on conspecifics
- Author
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Esteban Fernández-Juricic and Shannon R. Butler
- Subjects
0106 biological sciences ,Fovea Centralis ,Visual acuity ,Eye Movements ,genetic structures ,Vision ,Physiology ,Visual System ,Sensory Physiology ,Visual Acuity ,Social Sciences ,lcsh:Medicine ,01 natural sciences ,Predation ,Medicine and Health Sciences ,Psychology ,lcsh:Science ,Predator ,Mammals ,Multidisciplinary ,Animal Behavior ,biology ,05 social sciences ,Eukaryota ,Sensory Systems ,Starlings ,Vertebrates ,Head movements ,Sensory Perception ,Anatomy ,medicine.symptom ,Research Article ,Ocular Anatomy ,010603 evolutionary biology ,Birds ,Ocular System ,medicine ,Animals ,0501 psychology and cognitive sciences ,050102 behavioral science & comparative psychology ,Behavior ,Communication ,business.industry ,lcsh:R ,Organisms ,Biology and Life Sciences ,Eye movement ,biology.organism_classification ,Gaze ,eye diseases ,Sturnus ,Predatory Behavior ,Amniotes ,Fixation (visual) ,Cats ,Eyes ,lcsh:Q ,business ,Head ,Zoology ,Neuroscience - Abstract
Head movements allow birds with laterally placed eyes to move their centers of acute vision around and align them with objects of interest. Consequently, head movements have been used as indicator of fixation behavior (where gaze is maintained). However, studies on head movement behavior have not elucidated the degree to which birds use high-acuity or low-acuity vision. We studied how European starlings (Sturnus vulgaris) used high-acuity vision in the early stages of visual exploration of a stuffed cat (common terrestrial predator), a taxidermy Cooper’s hawk (common aerial predator), and a stuffed study skin of a conspecific. We found that starlings tended to use their high acuity vision when looking at predators, particularly, the cat was above chance levels. However, when they viewed a conspecific, they used high acuity vision as expected by chance. We did not observe a preference for the left or right center of acute vision. Our findings suggest that starlings exposed to a predator (particularly cats) may employ selective attention by using high-acuity vision to obtain quickly detailed information useful for a potential escape, but exposed to a social context may use divided attention by allocating similar levels high- and low-quality vision to monitor both conspecifics and the rest of the environment.
- Published
- 2018
27. Head-eye movement of collegiate baseball batters during fastball hitting
- Author
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Takatoshi Higuchi, Tomoyuki Nagami, Hiroki Nakata, and Kazuyuki Kanosue
- Subjects
Eye Movements ,Physiology ,Visual System ,Vision ,Computer science ,Sensory Physiology ,Social Sciences ,lcsh:Medicine ,Functional Laterality ,0302 clinical medicine ,Bats ,Medicine and Health Sciences ,Psychology ,Computer vision ,lcsh:Science ,Musculoskeletal System ,Mammals ,Multidisciplinary ,medicine.diagnostic_test ,05 social sciences ,Eukaryota ,Electrooculography ,Swing ,Cameras ,Sports Science ,Sensory Systems ,Biomechanical Phenomena ,Signal Filtering ,Optical Equipment ,Motor Skills ,Head Movements ,Vertebrates ,Ball (bearing) ,Engineering and Technology ,Sensory Perception ,Anatomy ,Research Article ,Sports ,Equipment ,Athletic Performance ,Baseball ,050105 experimental psychology ,Young Adult ,03 medical and health sciences ,Ocular System ,medicine ,Humans ,Animals ,0501 psychology and cognitive sciences ,Behavior ,business.industry ,lcsh:R ,Organisms ,Biology and Life Sciences ,Eye movement ,Saccadic masking ,Athletes ,Amniotes ,Signal Processing ,Recreation ,Eyes ,lcsh:Q ,Artificial intelligence ,business ,Head ,030217 neurology & neurosurgery ,Neuroscience - Abstract
Successful baseball hitting involves a combination of highly trained perceptual skills and forceful bat swing motions. The purpose of the present study was to quantify the horizontal movement of the head and eyes while baseball batters hit a fastball to clarify a visual strategy for this highly trained interceptive task. Six collegiate baseball players hit a fastball that was launched from a pitching machine. The ball speed was 31.9 m·s-1 for the Slow Ball Task and 40.3 m·s-1 for the Fast Ball Task. Horizontal head movements were analysed using images that were captured by two high-speed video cameras. The Horizontal eye movement was recorded with electrooculography. The angular speed of the horizontal head and eye movements during hitting were divided into four time periods (I-40 = 21–40% of total ball-flight, I-60 = 41–60% of total ball-flight, I-80 = 61–80% of total ball-flight, I-100 = 81–100% of total ball-flight) and analysed using analysis of variance and a Tukey post-hoc multiple-comparison. In the Slow Ball Task, the horizontal angular velocity of the head during I-80 was significantly faster than that during I-40 (p < 0.05). In the Fast Ball Task, the horizontal angular velocity of the head during I-80 was significantly faster than that during I-40 and I-60 (p < 0.05). These results indicated that the tracking motion of the head became faster as the launched ball came close to the batters, but there was no change in the angular tracking motion of the eyes. Therefore, rapid eye movement may not be suitable to accurately estimate the ball’s future location during fastball hitting based on the eye-centered coordinates. Our findings suggest that conventional vision training with a wide range of saccadic or smooth-pursuit eye movements does not reflect the characteristics of tracking strategies during baseball hitting.
- Published
- 2018
28. Locomotor illusions are generated by perceptual body-environment organization.
- Author
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Dobricki M, Weibel D, Angelini L, Mugellini E, and Mast FW
- Subjects
- Adolescent, Body Image, Female, Gait, Head Movements, Humans, Male, Photic Stimulation, Physical Stimulation, Proprioception physiology, Psychometrics, Space Perception physiology, Vibration, Walking, Young Adult, Illusions physiology, Illusions psychology, Locomotion, Motion Perception physiology, Virtual Reality
- Abstract
While one is walking, the stimulation by one's body forms a structure with the stimulation by the environment. This locomotor array of stimulation corresponds to the human-environment relation that one's body forms with the environment it is moving through. Thus, the perceptual experience of walking may arise from such a locomotor array of stimulation. Humans can also experience walking while they are sitting. In this case, there is no stimulation by one's walking body. Hence, one can experience walking although a basic component of a locomotor array of stimulation is missing. This may be facilitated by perception organizing the sensory input about one's body and environment into a perceptual structure that corresponds to a locomotor array of stimulation. We examined whether locomotor illusions are generated by this perceptual formation of a locomotor structure. We exposed sixteen seated individuals to environmental stimuli that elicited either the perceptual formation of a locomotor structure or that of a control structure. The study participants experienced distinct locomotor illusions when they were presented with environmental stimuli that elicited the perceptual formation of a locomotor structure. They did not experience distinct locomotor illusions when the stimuli instead elicited the perceptual formation of the control structure. These findings suggest that locomotor illusions are generated by the perceptual organization of sensory input about one's body and environment into a locomotor structure. This perceptual body-environment organization elucidates why seated human individuals experience the sensation of walking without any proprioceptive or kinaesthetic stimulation., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2021
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29. Temporal interpolation alters motion in fMRI scans: Magnitudes and consequences for artifact detection
- Author
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Peter A. Bandettini, Jonathan D. Power, Prantik Kundu, Alex Martin, and Mark Plitt
- Subjects
Computer science ,Image Processing ,Motion (physics) ,Diagnostic Radiology ,0302 clinical medicine ,Functional Magnetic Resonance Imaging ,Image Processing, Computer-Assisted ,Medicine and Health Sciences ,Computer vision ,Numerical Analysis ,Brain Mapping ,Multidisciplinary ,Data Processing ,medicine.diagnostic_test ,Radiology and Imaging ,05 social sciences ,Dynamics (mechanics) ,Software Engineering ,Magnetic Resonance Imaging ,Data Acquisition ,Head Movements ,Outlier ,Physical Sciences ,Medicine ,Engineering and Technology ,Anatomy ,Artifacts ,Information Technology ,Interpolation ,Research Article ,Quality Control ,Computer and Information Sciences ,Imaging Techniques ,Science ,Image processing ,Neuroimaging ,Research and Analysis Methods ,050105 experimental psychology ,03 medical and health sciences ,Diagnostic Medicine ,Motion estimation ,medicine ,Humans ,0501 psychology and cognitive sciences ,Artifact (error) ,business.industry ,Software Tools ,Biology and Life Sciences ,13. Climate action ,Signal Processing ,Artificial intelligence ,business ,Functional magnetic resonance imaging ,Head ,030217 neurology & neurosurgery ,Mathematics ,Neuroscience - Abstract
Head motion can be estimated at any point of fMRI image processing. Processing steps involving temporal interpolation (e.g., slice time correction or outlier replacement) often precede motion estimation in the literature. From first principles it can be anticipated that temporal interpolation will alter head motion in a scan. Here we demonstrate this effect and its consequences in five large fMRI datasets. Estimated head motion was reduced by 10-50% or more following temporal interpolation, and reductions were often visible to the naked eye. Such reductions make the data seem to be of improved quality. Such reductions also degrade the sensitivity of analyses aimed at detecting motion-related artifact and can cause a dataset with artifact to falsely appear artifact-free. These reduced motion estimates will be particularly problematic for studies needing estimates of motion in time, such as studies of dynamics. Based on these findings, it is sensible to obtain motion estimates prior to any image processing (regardless of subsequent processing steps and the actual timing of motion correction procedures, which need not be changed). We also find that outlier replacement procedures change signals almost entirely during times of motion and therefore have notable similarities to motion-targeting censoring strategies (which withhold or replace signals entirely during times of motion).
- Published
- 2017
30. A novel rat head gaze determination system based on optomotor responses
- Author
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Hiroshi Tomita, Toshiyuki Yamane, Takuya Akashi, Mengbo You, and Eriko Sugano
- Subjects
0301 basic medicine ,genetic structures ,Computer science ,Vision ,Image Processing ,Video Recording ,lcsh:Medicine ,Social Sciences ,Mice ,User-Computer Interface ,0302 clinical medicine ,Medicine and Health Sciences ,Image Processing, Computer-Assisted ,Psychology ,Computer vision ,lcsh:Science ,Mammals ,Multidisciplinary ,Applied Mathematics ,Simulation and Modeling ,Animal Models ,Experimental Organism Systems ,Head Movements ,Vertebrates ,Physical Sciences ,Engineering and Technology ,Sensory Perception ,Anatomy ,Algorithms ,Research Article ,Optimization ,Geometry ,Image processing ,Stimulus (physiology) ,Nose ,Research and Analysis Methods ,Rodents ,03 medical and health sciences ,Model Organisms ,Ocular System ,Animals ,Curvature ,business.industry ,lcsh:R ,Organisms ,Eye movement ,Biology and Life Sciences ,Observer (special relativity) ,Gaze ,Rats ,030104 developmental biology ,Face ,Fixation (visual) ,Signal Processing ,Amniotes ,Optomotor response ,Eyes ,lcsh:Q ,Artificial intelligence ,business ,Head ,030217 neurology & neurosurgery ,Mathematics ,Photic Stimulation ,Neuroscience ,Optometry - Abstract
The optomotor response of animals is commonly used to measure their visual performance, e.g., rats of different genetically altered strains or various drug tests. With the presentation of stimuli using computer screens or projectors, the common idea focuses on measuring the eye movement or head and/or body movement to characterize changes of the head gaze. However, traditional methods rely on either the invasive fixation of animals, or the judgment of a human observer who reports the stimulus-tracking movements. In this paper, we propose a novel head gaze determination system to automatically track the head movement of rats without artificial markers. The experiments were done to demonstrate the process of optimizing parameters in image processing. As a result, the head angle curve of the proposed method is consistent with that of ground-truth data annotated manually according to predefined rules. Hence, the proposed method provides a simple, convenient, and objective solution to automatically generate the head gaze orientations from massive amounts of recorded data for further visual performance analysis.
- Published
- 2017
31. Strength of baseline inter-trial correlations forecasts adaptive capacity in the vestibulo-ocular reflex
- Author
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Aaron L. Wong, Mark Shelhamer, Kara H. Beaton, and Steven B. Lowen
- Subjects
Multivariate analysis ,genetic structures ,Eye Movements ,Physiology ,Visual System ,Sensory Physiology ,Individuality ,lcsh:Medicine ,Social Sciences ,Audiology ,0302 clinical medicine ,Learning and Memory ,Mathematical and Statistical Techniques ,Medicine and Health Sciences ,Psychology ,lcsh:Science ,Musculoskeletal System ,Mathematics ,Principal Component Analysis ,Multidisciplinary ,Reflex, Vestibulo-Ocular ,Adaptation, Physiological ,Sensory Systems ,Behavioral data ,Fractals ,Head Movements ,Physical Sciences ,Anatomy ,Statistics (Mathematics) ,Research Article ,medicine.medical_specialty ,Ocular Anatomy ,Geometry ,Adaptation (eye) ,Research and Analysis Methods ,Retina ,03 medical and health sciences ,Ocular System ,medicine ,Learning ,Humans ,Statistical Methods ,Baseline (configuration management) ,Adaptive capacity ,lcsh:R ,Cognitive Psychology ,Eye movement ,Biology and Life Sciences ,030229 sport sciences ,Multivariate Analysis ,Reflex ,Eyes ,Cognitive Science ,lcsh:Q ,sense organs ,Vestibulo–ocular reflex ,Head ,030217 neurology & neurosurgery ,Psychomotor Performance ,Neuroscience - Abstract
Individual differences in sensorimotor adaptability may permit customized training protocols for optimum learning. Here, we sought to forecast individual adaptive capabilities in the vestibulo-ocular reflex (VOR). Subjects performed 400 head-rotation steps (400 trials) during a baseline test, followed by 20 min of VOR gain adaptation. All subjects exhibited mean baseline VOR gain of approximately 1.0, variable from trial to trial, and showed desired reductions in gain following adaptation with variation in extent across individuals. The extent to which a given subject adapted was inversely proportional to a measure of the strength and duration of baseline inter-trial correlations (β). β is derived from the decay of the autocorrelation of the sequence of VOR gains, and describes how strongly correlated are past gain values; it thus indicates how much the VOR gain on any given trial is informed by performance on previous trials. To maximize the time that images are stabilized on the retina, the VOR should maintain a gain close to 1.0 that is adjusted predominantly according to the most recent error; hence, it is not surprising that individuals who exhibit smaller β (weaker inter-trial correlations) also exhibited the best adaptation. Our finding suggests that the temporal structure of baseline behavioral data contains important information that may aid in forecasting adaptive capacities. This has significant implications for the development of personalized physical therapy protocols for patients, and for other cases when it is necessary to adjust motor programs to maintain movement accuracy in response to pathological and environmental changes.
- Published
- 2017
32. Vection is the main contributor to motion sickness induced by visual yaw rotation: Implications for conflict and eye movement theories
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Nooij, Suzanne A. E., Pretto, Paolo, Oberfeld, Daniel, Hecht, Heiko, and Bülthoff, Heinrich H.
- Subjects
Adult ,Male ,Eye Movements ,Rotation ,Vision ,Physiology ,Visual System ,Motion Sickness ,Cognitive Neuroscience ,Sensory Physiology ,Acceleration ,lcsh:Medicine ,Social Sciences ,Geometry ,Models, Biological ,Motor Reactions ,Motion ,Young Adult ,Ocular System ,Medicine and Health Sciences ,Psychology ,Humans ,lcsh:Science ,Musculoskeletal System ,Nystagmus, Optokinetic ,Physics ,lcsh:R ,Biology and Life Sciences ,Classical Mechanics ,Middle Aged ,Sensory Systems ,Postural Control ,Ellipses ,Head Movements ,Physical Sciences ,Visual Perception ,Eyes ,Cognitive Science ,lcsh:Q ,Sensory Perception ,Female ,Anatomy ,Head ,Mathematics ,Research Article ,Neuroscience - Abstract
This study investigated the role of vection (i.e., a visually induced sense of self-motion), optokinetic nystagmus (OKN), and inadvertent head movements in visually induced motion sickness (VIMS), evoked by yaw rotation of the visual surround. These three elements have all been proposed as contributing factors in VIMS, as they can be linked to different motion sickness theories. However, a full understanding of the role of each factor is still lacking because independent manipulation has proven difficult in the past. We adopted an integrative approach to the problem by obtaining measures of potentially relevant parameters in four experimental conditions and subsequently combining them in a linear mixed regression model. To that end, participants were exposed to visual yaw rotation in four separate sessions. Using a full factorial design, the OKN was manipulated by a fixation target (present/absent), and vection strength by introducing a conflict in the motion direction of the central and peripheral field of view (present/absent). In all conditions, head movements were minimized as much as possible. Measured parameters included vection strength, vection variability, OKN slow phase velocity, OKN frequency, the number of inadvertent head movements, and inadvertent head tilt. Results show that VIMS increases with vection strength, but that this relation varies among participants (R2 = 0.48). Regression parameters for vection variability, head and eye movement parameters were not significant. These results may seem to be in line with the Sensory Conflict theory on motion sickness, but we argue that a more detailed definition of the exact nature of the conflict is required to fully appreciate the relationship between vection and VIMS.
- Published
- 2017
33. An Objective Functional Characterisation of Head Movement Impairment in Individuals with Neck Muscle Weakness Due to Amyotrophic Lateral Sclerosis
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Pancani, S., Tindale, W., Shaw, P.J., McDermott, C.J., and Mazza, C.
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Male ,Sternum ,Muscle Physiology ,Muscle Functions ,Physiology ,Science ,Acceleration ,Pilot Projects ,Research and Analysis Methods ,Motor Neuron Diseases ,Neck Muscles ,Medicine and Health Sciences ,Humans ,Musculoskeletal System ,Skeleton ,Aged ,Muscle Weakness ,Physics ,Amyotrophic Lateral Sclerosis ,Biology and Life Sciences ,Classical Mechanics ,Neurodegenerative Diseases ,Muscle Analysis ,Middle Aged ,Electrophysiological Phenomena ,Bioassays and Physiological Analysis ,Neurology ,Case-Control Studies ,Head Movements ,Physical Sciences ,Medicine ,Female ,Anatomy ,Head ,Neck ,Research Article - Abstract
BackgroundNeck muscle weakness and head drop are well recognised in patients with Amyotrophic lateral sclerosis (ALS), but an objective characterisation of the consequent head movement impairment is lacking. The aim of this study was to quantitatively characterise head movements in ALS compared to aged matched controls.MethodsWe evaluated two groups, one of thirteen patients with ALS and one of thirteen age-matched controls, during the execution of a series of controlled head movements, performed while wearing two inertial sensors attached on the forehead and sternum, respectively. We quantified the differences between the two groups from the sensor data using indices of velocity, smoothness and movement coupling (intended as a measure of undesired out of plane movements).FindingsResults confirmed a general limitation in the ability of the ALS patients to perform and control head movements. High inter-patient variability was observed due to a wide range of observed functional impairment levels. The ability to extend the head backward and flex it laterally were the most compromised, with significantly lower angular velocity (P < 0.05, Cohen's d > 0.8), reduced smoothness and greater presence of coupled movements with respect to the controls. A significant reduction of angular velocity (P < 0.05, Cohen's d > 0.8) in extension, axial rotation and lateral flexion was observed when patients were asked to perform the movements as fast as possible.InterpretationThis pilot study is the first study providing a functional objective quantification of head movements in ALS. Further work involving different body areas and correlation with existing methods of evaluating neuromuscular function, such as dynamometry and EMG, is needed to explore the use of this approach as a marker of disease progression in ALS.
- Published
- 2017
34. Influence of Head Motion on the Accuracy of 3D Reconstruction with Cone-Beam CT: Landmark Identification Errors in Maxillofacial Surface Model
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Kyung Min Lee, Jin-Myoung Song, Jin-Hyoung Cho, and Hyeon-Shik Hwang
- Subjects
Cone beam computed tomography ,Image Processing ,Dental and Oral Procedures ,lcsh:Medicine ,Motion controller ,030218 nuclear medicine & medical imaging ,Diagnostic Radiology ,0302 clinical medicine ,Medicine and Health Sciences ,Image Processing, Computer-Assisted ,Maxilla ,lcsh:Science ,Musculoskeletal System ,Tomography ,Orthodontics ,Multidisciplinary ,Radiology and Imaging ,3D reconstruction ,Cone-Beam Computed Tomography ,Magnetic Resonance Imaging ,Head Movements ,Engineering and Technology ,Anatomy ,Orthognathic Jaw Surgery ,Rotation (mathematics) ,Geology ,Research Article ,medicine.medical_specialty ,Scanner ,Computer and Information Sciences ,Rotation ,Imaging Techniques ,Surgical and Invasive Medical Procedures ,Neuroimaging ,Research and Analysis Methods ,Models, Biological ,Computer Software ,03 medical and health sciences ,Imaging, Three-Dimensional ,Diagnostic Medicine ,medicine ,Humans ,Diagnostic Errors ,Four-Dimensional Computed Tomography ,Skeleton ,Landmark ,lcsh:R ,Skull ,Biology and Life Sciences ,030206 dentistry ,Surgery ,Face ,Signal Processing ,Head (vessel) ,lcsh:Q ,Head ,Positron Emission Tomography ,Neuroscience - Abstract
Purpose The purpose of this study was to investigate the influence of head motion on the accuracy of three-dimensional (3D) reconstruction with cone-beam computed tomography (CBCT) scan. Materials and Methods Fifteen dry skulls were incorporated into a motion controller which simulated four types of head motion during CBCT scan: 2 horizontal rotations (to the right/to the left) and 2 vertical rotations (upward/downward). Each movement was triggered to occur at the start of the scan for 1 second by remote control. Four maxillofacial surface models with head motion and one control surface model without motion were obtained for each skull. Nine landmarks were identified on the five maxillofacial surface models for each skull, and landmark identification errors were compared between the control model and each of the models with head motion. Results Rendered surface models with head motion were similar to the control model in appearance; however, the landmark identification errors showed larger values in models with head motion than in the control. In particular, the Porion in the horizontal rotation models presented statistically significant differences (P < .05). Statistically significant difference in the errors between the right and left side landmark was present in the left side rotation which was opposite direction to the scanner rotation (P < .05). Conclusions Patient movement during CBCT scan might cause landmark identification errors on the 3D surface model in relation to the direction of the scanner rotation. Clinicians should take this into consideration to prevent patient movement during CBCT scan, particularly horizontal movement.
- Published
- 2016
35. Head Motion and Inattention/Hyperactivity Share Common Genetic Influences: Implications for fMRI Studies of ADHD
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Margaret J. Wright, Baptiste Couvy-Duchesne, Ian B. Hickie, Jane L. Ebejer, Nathan A. Gillespie, Sarah E. Medland, Nicholas G. Martin, Greig I. de Zubicaray, David L. Duffy, Paul M. Thompson, and Katie L. McMahon
- Subjects
Adult ,Male ,Adolescent ,Mothers ,lcsh:Medicine ,Neuroimaging ,Hyperkinesis ,Impulsivity ,050105 experimental psychology ,03 medical and health sciences ,0302 clinical medicine ,Self-report study ,Covariate ,medicine ,Diseases in Twins ,Twins, Dizygotic ,Humans ,0501 psychology and cognitive sciences ,Young adult ,Association (psychology) ,lcsh:Science ,Multidisciplinary ,medicine.diagnostic_test ,05 social sciences ,lcsh:R ,Brain ,Twins, Monozygotic ,Magnetic Resonance Imaging ,Phenotype ,Attention Deficit Disorder with Hyperactivity ,Head Movements ,Impulsive Behavior ,Trait ,Female ,lcsh:Q ,Self Report ,medicine.symptom ,Psychology ,Functional magnetic resonance imaging ,030217 neurology & neurosurgery ,Clinical psychology ,Research Article - Abstract
Head motion (HM) is a well known confound in analyses of functional MRI (fMRI) data. Neuroimaging researchers therefore typically treat HM as a nuisance covariate in their analyses. Even so, it is possible that HM shares a common genetic influence with the trait of interest. Here we investigate the extent to which this relationship is due to shared genetic factors, using HM extracted from resting-state fMRI and maternal and self report measures of Inattention and Hyperactivity-Impulsivity from the Strengths and Weaknesses of ADHD Symptoms and Normal Behaviour (SWAN) scales. Our sample consisted of healthy young adult twins (N = 627 (63% females) including 95 MZ and 144 DZ twin pairs, mean age 22, who had mother-reported SWAN; N = 725 (58% females) including 101 MZ and 156 DZ pairs, mean age 25, with self reported SWAN). This design enabled us to distinguish genetic from environmental factors in the association between head movement and ADHD scales. HM was moderately correlated with maternal reports of Inattention (r = 0.17, p-value = 7.4E-5) and Hyperactivity-Impulsivity (r = 0.16, p-value = 2.9E-4), and these associations were mainly due to pleiotropic genetic factors with genetic correlations [95% CIs] of rg = 0.24 [0.02, 0.43] and rg = 0.23 [0.07, 0.39]. Correlations between self-reports and HM were not significant, due largely to increased measurement error. These results indicate that treating HM as a nuisance covariate in neuroimaging studies of ADHD will likely reduce power to detect between-group effects, as the implicit assumption of independence between HM and Inattention or Hyperactivity-Impulsivity is not warranted. The implications of this finding are problematic for fMRI studies of ADHD, as failing to apply HM correction is known to increase the likelihood of false positives. We discuss two ways to circumvent this problem: censoring the motion contaminated frames of the RS-fMRI scan or explicitly modeling the relationship between HM and Inattention or Hyperactivity-Impulsivity.
- Published
- 2016
36. Accurate face alignment and adaptive patch selection for heart rate estimation from videos under realistic scenarios
- Author
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Kwang-Ting Cheng, Xin Yang, and Zhiwei Wang
- Subjects
Male ,Light ,Physiology ,Computer science ,lcsh:Medicine ,Skin Pigmentation ,02 engineering and technology ,Electrocardiography ,Heart Rate ,Margin (machine learning) ,Medicine and Health Sciences ,Image Processing, Computer-Assisted ,0202 electrical engineering, electronic engineering, information engineering ,lcsh:Science ,Skin ,Multidisciplinary ,Body Fluids ,Signal Filtering ,Facial Expression ,Bioassays and Physiological Analysis ,Blood ,Head Movements ,Engineering and Technology ,Female ,020201 artificial intelligence & image processing ,Anatomy ,Research Article ,0206 medical engineering ,Cardiology ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Image processing ,Research and Analysis Methods ,Ocular System ,Heart Rate Determination ,Humans ,Face detection ,Facial expression ,business.industry ,Electrophysiological Techniques ,lcsh:R ,Biology and Life Sciences ,Videotape Recording ,Pattern recognition ,020601 biomedical engineering ,Speech Signal Processing ,Face ,Face (geometry) ,Signal Processing ,Eyes ,lcsh:Q ,Cardiac Electrophysiology ,Artificial intelligence ,business ,Head - Abstract
Non-contact heart rate (HR) measurement from facial videos has attracted high interests due to its convenience and cost effectiveness. However, accurate and robust HR estimation under various realistic scenarios remain a very challenging problem. In this paper, we develop a novel system which can achieve a robust and accurate HR estimation under those challenging scenarios. First, to minimize tracking-artifacts arising from large head motions and facial expressions, we propose a joint face detection and alignment method which can produce alignment-friendly facial bounding boxes with reliable initial facial shapes, facilitating accurate and robust face alignment even in the presence of large pose variations and expressions. Second, different from most existing methods [1-5] which derive pulse signals from predetermined grid cells (i.e. local patches), our patches are varying-sized triangles generated adaptively to exclude negative effects from non-rigid facial motions. Third, we propose an adaptive patch selection method to choose patches which contain skin regions and are more likely to contain useful information, followed by an independent component analysis, for an accurate HR estimate. Extensive experiments on both public datasets and our own dataset demonstrated that, comparing with the state-of-the-art methods [1-3], our method reduces the root mean square error (RMSE) by a large margin, ranging from 12% to 63%, and can provide a robust and accurate estimation under various challenging scenarios.
- Published
- 2018
37. Effects of driver compensatory behaviour on risks of critical pedestrian collisions under simulated visual field defects.
- Author
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Lee J and Itoh M
- Subjects
- Adult, Female, Head Movements, Humans, Kaplan-Meier Estimate, Male, Time Factors, Young Adult, Accidents, Traffic, Automobile Driving, Behavior, Computer Simulation, Pedestrians, Visual Fields physiology
- Abstract
Compensatory behaviour is regarded as a helpful strategy to mediate drivers' deteriorated hazard perception ability due to visual field defects. However, helpfulness of compensatory behaviour for drivers with advanced visual field defects has largely unexplored. This study aims to clarify the effectiveness and limitation of compensatory head movements in critical situations where included pedestrians stepping off a sidewalk under the simulation of advanced visual defects. 18 healthy-sighted drivers participated the data collection that was conducted in a driving simulator under three driving conditions: (1) without visual impairment, (2) with visual impairment and not performing active compensation, and (3) with visual impairment but performing active compensation. The result showed that active compensation led quick accelerator and brake response times, reducing the risk and number of pedestrian collisions. The active compensation led a decrease in the number of non-responses to hazardous pedestrians compared to while driving not performing compensation. However, the compensation could not reduce the number of pedestrian collisions to those of healthy-sighted drivers. Compensatory viewing behaviour contributed to improved driving performance as well as has limits to lead driving performance like healthy-sighted drivers. Developing driver assistance systems and practical compensatory strategies concerning the degrees of impairment and traffic conditions may provide opportunities to improve driving safety deteriorated hazard perception for visually impaired drivers., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2020
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38. Differences between racing and non-racing drivers: A simulator study using eye-tracking
- Author
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Peter Van Leeuwen, Riender Happee, Joost C. F. de Winter, and Stefan de Groot
- Subjects
Questionnaires ,Male ,Eye Movements ,Physiology ,Visual System ,Sensory Physiology ,lcsh:Medicine ,Transportation ,Task (project management) ,0302 clinical medicine ,Medicine and Health Sciences ,lcsh:Science ,media_common ,Multidisciplinary ,Cognition ,Transportation Infrastructure ,Navigation ,Sensory Systems ,Sports Science ,Research Design ,Head Movements ,Physical Sciences ,Engineering and Technology ,Steering ,Psychology ,Research Article ,Sports ,Automobile Driving ,Cognitive Neuroscience ,media_common.quotation_subject ,Geometry ,Motor Activity ,Research and Analysis Methods ,Civil Engineering ,03 medical and health sciences ,Perception ,Tangents ,Reaction Time ,Humans ,Computer Simulation ,Cognitive skill ,Simulation ,Behavior ,Survey Research ,Mechanical Engineering ,lcsh:R ,Significant difference ,Biology and Life Sciences ,Eye movement ,030229 sport sciences ,Gaze ,Roads ,Cognitive Science ,Recreation ,Eye tracking ,lcsh:Q ,Brakes ,Mathematics ,030217 neurology & neurosurgery ,Neuroscience - Abstract
Motorsport has developed into a professional international competition. However, limited research is available on the perceptual and cognitive skills of racing drivers. By means of a racing simulator, we compared the driving performance of seven racing drivers with ten non-racing drivers. Participants were tasked to drive the fastest possible lap time. Additionally, both groups completed a choice reaction time task and a tracking task. Results from the simulator showed faster lap times, higher steering activity, and a more optimal racing line for the racing drivers than for the non-racing drivers. The non-racing drivers' gaze behavior corresponded to the tangent point model, whereas racing drivers showed a more variable gaze behavior combined with larger head rotations while cornering. Results from the choice reaction time task and tracking task showed no statistically significant difference between the two groups. Our results are consistent with the current consensus in sports sciences in that task-specific differences exist between experts and novices while there are no major differences in general cognitive and motor abilities.
- Published
- 2017
39. Forced fusion in multisensory heading estimation
- Author
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de Winkel, Ksander N., Katliar, Mikhail, and Bülthoff, Heinrich H.
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Adult ,Male ,Adolescent ,Movement ,lcsh:R ,Motion Perception ,lcsh:Medicine ,Middle Aged ,Young Adult ,Head Movements ,Humans ,Female ,lcsh:Q ,lcsh:Science ,Algorithms ,Photic Stimulation ,Research Article ,Aged - Abstract
It has been shown that the Central Nervous System (CNS) integrates visual and inertial information in heading estimation for congruent multisensory stimuli and stimuli with small discrepancies. Multisensory information should, however, only be integrated when the cues are redundant. Here, we investigated how the CNS constructs an estimate of heading for combinations of visual and inertial heading stimuli with a wide range of discrepancies. Participants were presented with 2s visual-only and inertial-only motion stimuli, and combinations thereof. Discrepancies between visual and inertial heading ranging between 0-90° were introduced for the combined stimuli. In the unisensory conditions, it was found that visual heading was generally biased towards the fore-aft axis, while inertial heading was biased away from the fore-aft axis. For multisensory stimuli, it was found that five out of nine participants integrated visual and inertial heading information regardless of the size of the discrepancy; for one participant, the data were best described by a model that explicitly performs causal inference. For the remaining three participants the evidence could not readily distinguish between these models. The finding that multisensory information is integrated is in line with earlier findings, but the finding that even large discrepancies are generally disregarded is surprising. Possibly, people are insensitive to discrepancies in visual-inertial heading angle because such discrepancies are only encountered in artificial environments, making a neural mechanism to account for them otiose. An alternative explanation is that detection of a discrepancy may depend on stimulus duration, where sensitivity to detect discrepancies differs between people.
- Published
- 2015
40. Eye-head coordination for visual cognitive processing
- Author
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Yu Fang, Ryoichi Nakashima, Kazumichi Matsumiya, Ichiro Kuriki, and Satoshi Shioiri
- Subjects
Adult ,Male ,Eye Movements ,genetic structures ,Poison control ,lcsh:Medicine ,Visual processing ,Young Adult ,Humans ,lcsh:Science ,Vision, Ocular ,Visual search ,Multidisciplinary ,lcsh:R ,Eye movement ,Gaze ,eye diseases ,Visual field ,Head Movements ,Fixation (visual) ,Eye tracking ,Female ,lcsh:Q ,sense organs ,Psychology ,Psychomotor Performance ,Cognitive psychology ,Research Article - Abstract
We investigated coordinated movements between the eyes and head (“eye-head coordination”) in relation to vision for action. Several studies have measured eye and head movements during a single gaze shift, focusing on the mechanisms of motor control during eye-head coordination. However, in everyday life, gaze shifts occur sequentially and are accompanied by movements of the head and body. Under such conditions, visual cognitive processing influences eye movements and might also influence eye-head coordination because sequential gaze shifts include cycles of visual processing (fixation) and data acquisition (gaze shifts). In the present study, we examined how the eyes and head move in coordination during visual search in a large visual field. Subjects moved their eyes, head, and body without restriction inside a 360° visual display system. We found patterns of eye-head coordination that differed those observed in single gaze-shift studies. First, we frequently observed multiple saccades during one continuous head movement, and the contribution of head movement to gaze shifts increased as the number of saccades increased. This relationship between head movements and sequential gaze shifts suggests eye-head coordination over several saccade-fixation sequences; this could be related to cognitive processing because saccade-fixation cycles are the result of visual cognitive processing. Second, distribution bias of eye position during gaze fixation was highly correlated with head orientation. The distribution peak of eye position was biased in the same direction as head orientation. This influence of head orientation suggests that eye-head coordination is involved in gaze fixation, when the visual system processes retinal information. This further supports the role of eye-head coordination in visual cognitive processing.
- Published
- 2015
41. The Neural Correlates of Shoulder Apprehension: A Functional MRI Study
- Author
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Noritaka Hamano, Tsutomu Kobayashi, Atsushi Yamamoto, Daisuke Shimoyama, Yoshito Tsushima, Haku Iizuka, Kenji Takagishi, Toshihisa Osawa, Hitoshi Shitara, Takashi Hanakawa, Tsuyoshi Sasaki, and Tsuyoshi Ichinose
- Subjects
Adult ,Male ,Shoulder ,medicine.medical_specialty ,Imagery, Psychotherapy ,Brain activity and meditation ,Statistics as Topic ,lcsh:Medicine ,Somatosensory system ,Amygdala ,Motion ,Young Adult ,Physical medicine and rehabilitation ,Motor imagery ,Task Performance and Analysis ,Neuroplasticity ,medicine ,Humans ,lcsh:Science ,Brain Mapping ,Neural correlates of consciousness ,Multidisciplinary ,medicine.diagnostic_test ,business.industry ,lcsh:R ,Hemodynamics ,Brain ,Confounding Factors, Epidemiologic ,Anterior shoulder ,Magnetic Resonance Imaging ,medicine.anatomical_structure ,Head Movements ,Female ,lcsh:Q ,Functional magnetic resonance imaging ,business ,psychological phenomena and processes ,Research Article - Abstract
Although shoulder apprehension is an established clinical finding and is important for the prevention of shoulder dislocation, how this subjective perception is evoked remains unclear. We elucidated the functional neuroplasticity associated with apprehension in patients with recurrent anterior shoulder instability (RSI) using functional magnetic resonance imaging (fMRI). Twelve healthy volunteers and 14 patients with right-sided RSI performed a motor imagery task and a passive shoulder motion task. Brain activity was compared between healthy participants and those with RSI and was correlated with the apprehension intensity reported by participants after each task. Compared to healthy volunteers, participants with RSI exhibited decreased brain activity in the motor network, but increased activity in the hippocampus and amygdala. During the passive motion task, participants with RSI exhibited decreased activity in the left premotor and primary motor/somatosensory areas. Furthermore, brain activity was correlated with apprehension intensity in the left amygdala and left thalamus during the motor imagery task (memory-induced), while a correlation between apprehension intensity and brain activity was found in the left prefrontal cortex during the passive motion task (instability-induced). Our findings provide insight into the pathophysiology of RSI by identifying its associated neural alterations. We elucidated that shoulder apprehension was induced by two different factors, namely instability and memory.
- Published
- 2015
42. Gaze behavior in one-handed catching and its relation with interceptive performance: what the eyes can't tell
- Author
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Benedetta Cesqui, Maura Mezzetti, Andrea d'Avella, and Francesco Lacquaniti
- Subjects
Adult ,Male ,medicine.medical_specialty ,Eye Movements ,genetic structures ,Science ,Kinematics ,Settore BIO/09 ,050105 experimental psychology ,Visual pursuit ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Physical medicine and rehabilitation ,medicine ,Humans ,0501 psychology and cognitive sciences ,VISUAL-SEARCH ,TEMPORAL CONSTRAINTS ,TARGET MOTION ,REACTION-TIME ,MOVEMENTS ,BALL ,PURSUIT ,COORDINATION ,INFORMATION ,SMOOTH ,Multidisciplinary ,05 social sciences ,Eye movement ,Models, Theoretical ,Hand ,Gaze ,eye diseases ,Head Movements ,Ball (bearing) ,Head movements ,Medicine ,Female ,Psychology ,human activities ,030217 neurology & neurosurgery ,Algorithms ,Psychomotor Performance ,Research Article - Abstract
In ball sports, it is usually acknowledged that expert athletes track the ball more accurately than novices. However, there is also evidence that keeping the eyes on the ball is not always necessary for interception. Here we aimed at gaining new insights on the extent to which ocular pursuit performance is related to catching performance. To this end, we analyzed eye and head movements of nine subjects catching a ball projected by an actuated launching apparatus. Four different ball flight durations and two different ball arrival heights were tested and the quality of ocular pursuit was characterized by means of several timing and accuracy parameters. Catching performance differed across subjects and depended on ball flight characteristics. All subjects showed a similar sequence of eye movement events and a similar modulation of the timing of these events in relation to the characteristics of the ball trajectory. On a trial-by-trial basis there was a significant relationship only between pursuit duration and catching performance, confirming that keeping the eyes on the ball longer increases catching success probability. Ocular pursuit parameters values and their dependence on flight conditions as well as the eye and head contributions to gaze shift differed across subjects. However, the observed average individual ocular behavior and the eye-head coordination patterns were not directly related to the individual catching performance. These results suggest that several oculomotor strategies may be used to gather information on ball motion, and that factors unrelated to eye movements may underlie the observed differences in interceptive performance.
- Published
- 2015
43. Reading from a Head-Fixed Display during Walking: Adverse Effects of Gaze Stabilization Mechanisms
- Author
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Borg, Olivier, Casanova, Remy, Bootsma, Reinoud J., Oxylane Research (Oxylane), OXYLANE RESEARCH, Institut des Sciences du Mouvement Etienne Jules Marey (ISM), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Adult ,Male ,Eye Movements ,genetic structures ,[SDV]Life Sciences [q-bio] ,lcsh:Medicine ,Walking ,HUMAN VESTIBULOOCULAR REFLEX ,Young Adult ,VIEWING DISTANCE ,CONTRAST SENSITIVITY ,Humans ,FIXATION DISTANCE ,lcsh:Science ,[SDV.NEU.PC]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]/Psychology and behavior ,TARGET DISTANCE ,lcsh:R ,Models, Theoretical ,EYE-MOVEMENT RESPONSES ,Reading ,RETINAL IMAGE ,Head Movements ,VISUAL-VESTIBULAR INTERACTION ,Female ,lcsh:Q ,SMOOTH-PURSUIT ,PERIPHERAL-VISION ,Algorithms ,Photic Stimulation ,Research Article - Abstract
International audience; Reading performance during standing and walking was assessed for information presented on earth-fixed and head-fixed displays by determining the minimal duration during which a numerical time stimulus needed to be presented for 50% correct naming answers. Reading from the earth-fixed display was comparable during standing and walking, with optimal performance being attained for visual character sizes in the range of 0.2 degrees to 1 degrees. Reading from the head-fixed display was impaired for small (0.2-0.3 degrees) and large (5 degrees) visual character sizes, especially during walking. Analysis of head and eye movements demonstrated that retinal slip was larger during walking than during standing, but remained within the functional acuity range when reading from the earth-fixed display. The detrimental effects on performance of reading from the head-fixed display during walking could be attributed to loss of acuity resulting from large retinal slip. Because walking activated the angular vestibulo-ocular reflex, the resulting compensatory eye movements acted to stabilize gaze on the information presented on the earth-fixed display but destabilized gaze from the information presented on the head-fixed display. We conclude that the gaze stabilization mechanisms that normally allow visual performance to be maintained during physical activity adversely affect reading performance when the information is presented on a display attached to the head.
- Published
- 2015
44. Integration of Semi-Circular Canal and Otolith Cues for Direction Discrimination during Eccentric Rotations
- Author
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Soyka, Florian, Bülthoff, Heinrich H., and Barnett-Cowan, Michael
- Subjects
Adult ,Male ,Rotation ,Acceleration ,lcsh:R ,Motion Perception ,lcsh:Medicine ,Reflex, Vestibulo-Ocular ,Semicircular Canals ,Otolithic Membrane ,Young Adult ,Head Movements ,Psychophysics ,Humans ,Female ,lcsh:Q ,Cues ,lcsh:Science ,Head ,Research Article - Abstract
Humans are capable of moving about the world in complex ways. Every time we move, our self-motion must be detected and interpreted by the central nervous system in order to make appropriate sequential movements and informed decisions. The vestibular labyrinth consists of two unique sensory organs the semi-circular canals and the otoliths that are specialized to detect rotation and translation of the head, respectively. While thresholds for pure rotational and translational self-motion are well understood surprisingly little research has investigated the relative role of each organ on thresholds for more complex motion. Eccentric (off-center) rotations during which the participant faces away from the center of rotation stimulate both organs and are thus well suited for investigating integration of rotational and translational sensory information. Ten participants completed a psychophysical direction discrimination task for pure head-centered rotations, translations and eccentric rotations with 5 different radii. Discrimination thresholds for eccentric rotations reduced with increasing radii, indicating that additional tangential accelerations (which increase with radius length) increased sensitivity. Two competing models were used to predict the eccentric thresholds based on the pure rotation and translation thresholds: one assuming that information from the two organs is integrated in an optimal fashion and another assuming that motion discrimination is solved solely by relying on the sensor which is most strongly stimulated. Our findings clearly show that information from the two organs is integrated. However the measured thresholds for 3 of the 5 eccentric rotations are even more sensitive than predictions from the optimal integration model suggesting additional non-vestibular sources of information may be involved.
- Published
- 2015
45. Discriminative analysis of Parkinson's disease based on whole-brain functional connectivity
- Author
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Wanqun Yang, Yuhu Zhang, Yuanqing Li, Jinyi Long, Jieying Feng, Biao Huang, and Yongbin Chen
- Subjects
Male ,Parkinson's disease ,Support Vector Machine ,lcsh:Medicine ,Disease ,Bioinformatics ,Sensitivity and Specificity ,Neuroimaging ,Discriminative model ,Cerebellum ,Connectome ,Medicine ,Humans ,lcsh:Science ,Default mode network ,Aged ,Cerebral Cortex ,Multidisciplinary ,medicine.diagnostic_test ,business.industry ,lcsh:R ,Discriminant Analysis ,Parkinson Disease ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Support vector machine ,Early Diagnosis ,Case-Control Studies ,Head Movements ,Pattern recognition (psychology) ,Female ,lcsh:Q ,Nerve Net ,business ,Functional magnetic resonance imaging ,Neuroscience ,Research Article - Abstract
Recently, there has been an increasing emphasis on applications of pattern recognition and neuroimaging techniques in the effective and accurate diagnosis of psychiatric or neurological disorders. In the present study, we investigated the whole-brain resting-state functional connectivity patterns of Parkinson's disease (PD), which are expected to provide additional information for the clinical diagnosis and treatment of this disease. First, we computed the functional connectivity between each pair of 116 regions of interest derived from a prior atlas. The most discriminative features based on Kendall tau correlation coefficient were then selected. A support vector machine classifier was employed to classify 21 PD patients with 26 demographically matched healthy controls. This method achieved a classification accuracy of 93.62% using leave-one-out cross-validation, with a sensitivity of 90.47% and a specificity of 96.15%. The majority of the most discriminative functional connections were located within or across the default mode, cingulo-opercular and frontal-parietal networks and the cerebellum. These disease-related resting-state network alterations might play important roles in the pathophysiology of this disease. Our results suggest that analyses of whole-brain resting-state functional connectivity patterns have the potential to improve the clinical diagnosis and treatment evaluation of PD.
- Published
- 2015
46. Bumblebee Homing: The Fine Structure of Head Turning Movements
- Author
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Boeddeker, Norbert, Mertes, Marcel, Dittmar, Laura, and Egelhaaf, Martin
- Subjects
Behavior, Animal ,lcsh:R ,Video Recording ,lcsh:Medicine ,Bees ,Flight, Animal ,Head Movements ,Orientation ,Animals ,lcsh:Q ,Stereotyped Behavior ,lcsh:Science ,Research Article - Abstract
Changes in flight direction in flying insects are largely due to roll, yaw and pitch rotations of their body. Head orientation is stabilized for most of the time by counter rotation. Here, we use high-speed video to analyse head- and body-movements of the bumblebee Bombus terrestris while approaching and departing from a food source located between three landmarks in an indoor flight-arena. The flight paths consist of almost straight flight segments that are interspersed with rapid turns. These short and fast yaw turns ("saccades") are usually accompanied by even faster head yaw turns that change gaze direction. Since a large part of image rotation is thereby reduced to brief instants of time, this behavioural pattern facilitates depth perception from visual motion parallax during the intersaccadic intervals. The detailed analysis of the fine structure of the bees' head turning movements shows that the time course of single head saccades is very stereotypical. We find a consistent relationship between the duration, peak velocity and amplitude of saccadic head movements, which in its main characteristics resembles the so-called "saccadic main sequence" in humans. The fact that bumblebee head saccades are highly stereotyped as in humans, may hint at a common principle, where fast and precise motor control is used to reliably reduce the time during which the retinal images moves.
- Published
- 2015
47. Does Changing Vertical Disparity Induce Horizontal Head Movement?
- Author
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Toru Maekawa and Hirohiko Kaneko
- Subjects
Adult ,Male ,Vision Disparity ,genetic structures ,media_common.quotation_subject ,Science ,education ,Poison control ,Eye muscle ,Stimulus (physiology) ,Visual Disparity ,fluids and secretions ,Perception ,parasitic diseases ,Humans ,media_common ,Depth Perception ,Multidisciplinary ,Fourier Analysis ,Eye movement ,Geodesy ,body regions ,Head Movements ,Medicine ,Depth perception ,Geology ,Research Article - Abstract
Theoretically, one can estimate the direction of an object that is relative to the head using vertical disparity if the distance from the head to the object is known. However, several reports describe vertical disparity as having little or no effect on the perception of visual direction. It has been suggested, however, that the visual processes involved in action are different from those involved in perception, and the effect of visual disparity on action has not been investigated in previous studies. This study investigated the influence of vertical disparity on the stability of head direction as a motor response to visual information. We presented a stimulus consisting of horizontal lines with vertical size-disparity oscillation, and examined whether the stimulus affected the subject’s head movement. The results showed that the head movement in the condition of vertical size-disparity oscillation was not significantly different from that in the condition of no disparity oscillation. Our results suggest that, despite theoretical validity, vertical disparity is not used for controlling head movement.
- Published
- 2015
48. Opioid-Induced Nausea Involves a Vestibular Problem Preventable by Head-Rest
- Author
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Nadine Lehnen, Fabian Heuser, Murat Sağlam, Christian M Schulz, Klaus J Wagner, Masakatsu Taki, Eberhard F Kochs, Klaus Jahn, Thomas Brandt, Stefan Glasauer, and Erich Schneider
- Subjects
Adult ,Male ,lcsh:R ,lcsh:Medicine ,Nausea ,Reflex, Vestibulo-Ocular ,Analgesics, Opioid ,Remifentanil ,Piperidines ,Head Movements ,Humans ,lcsh:Q ,lcsh:Science ,Research Article - Abstract
Background and Aims Opioids are indispensable for pain treatment but may cause serious nausea and vomiting. The mechanism leading to these complications is not clear. We investigated whether an opioid effect on the vestibular system resulting in corrupt head motion sensation is causative and, consequently, whether head-rest prevents nausea. Methods Thirty-six healthy men (26.6±4.3 years) received an opioid remifentanil infusion (45 min, 0.15 μg/kg/min). Outcome measures were the vestibulo-ocular reflex (VOR) gain determined by video-head-impulse-testing, and nausea. The first experiment (n = 10) assessed outcome measures at rest and after a series of five 1-Hz forward and backward head-trunk movements during one-time remifentanil administration. The second experiment (n = 10) determined outcome measures on two days in a controlled crossover design: (1) without movement and (2) with a series of five 1-Hz forward and backward head-trunk bends 30 min after remifentanil start. Nausea was psychophysically quantified (scale from 0 to 10). The third controlled crossover experiment (n = 16) assessed nausea (1) without movement and (2) with head movement; isolated head movements consisting of the three axes of rotation (pitch, roll, yaw) were imposed 20 times at a frequency of 1 Hz in a random, unpredictable order of each of the three axes. All movements were applied manually, passively with amplitudes of about ± 45 degrees. Results The VOR gain decreased during remifentanil administration (p
- Published
- 2014
49. Effects of head tilt on visual field testing with a head-mounted perimeter imo
- Author
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Marika Yamashita, Mariko Eura, Sachiko Okuyama, Yasutaka Chiba, Kenzo Yamanaka, Makoto Aihara, Shigeki Hashimoto, Takuya Numata, Shinji Kimura, Chota Matsumoto, Yoshikazu Shimomura, Sayaka Yamao, and Hiroki Nomoto
- Subjects
Male ,Eye Movements ,Light ,Physiology ,Visual System ,Sensory Physiology ,Iris ,lcsh:Medicine ,Blindness ,Rotation ,Otolith ,Luminance ,0302 clinical medicine ,Medicine and Health Sciences ,lcsh:Science ,Visual Impairments ,Physics ,Multidisciplinary ,Electromagnetic Radiation ,Blind spot ,Sinusoidal model ,Sensory Systems ,Visual field ,Amplitude ,Head Movements ,Inner Ear ,Physical Sciences ,Engineering and Technology ,Regression Analysis ,Female ,Anatomy ,Research Article ,Adult ,Visible Light ,Ocular Anatomy ,Perimeter ,03 medical and health sciences ,Optics ,Ocular System ,Humans ,business.industry ,lcsh:R ,Biology and Life Sciences ,Diodes ,Ophthalmology ,Ears ,030221 ophthalmology & optometry ,Eyes ,Visual Field Tests ,Head (vessel) ,lcsh:Q ,Electronics ,Visual Fields ,business ,Head ,Light-Emitting Diodes ,030217 neurology & neurosurgery ,Neuroscience - Abstract
Purpose A newly developed head-mounted perimeter termed “imo” enables visual field (VF) testing without a fixed head position. Because the positional relationship between the subject’s head and the imo is fixed, the effects of head position changes on the test results are small compared with those obtained using a stationary perimeter. However, only ocular counter-roll (OCR) induced by head tilt might affect VF testing. To quantitatively reveal the effects of head tilt and OCR on the VF test results, we investigated the associations among the head-tilt angle, OCR amplitude and VF testing results. Subjects and methods For 20 healthy subjects, we binocularly recorded static OCR (s-OCR) while tilting the subject’s head at an arbitrary angle ranging from 0° to 60° rightward or leftward in 10° increments. By monitoring iris patterns, we evaluated the s-OCR amplitude. We also performed blind spot detection while tilting the subject’s head by an arbitrary angle ranging from 0° to 50° rightward or leftward in 10° increments to calculate the angle by which the blind spot rotates because of head tilt. Results The association between s-OCR amplitude and head-tilt angle showed a sinusoidal relationship. In blind spot detection, the blind spot rotated to the opposite direction of the head tilt, and the association between the rotation angle of the blind spot and the head-tilt angle also showed a sinusoidal relationship. The rotation angle of the blind spot was strongly correlated with the s-OCR amplitude (R2≥0.94, p
- Published
- 2017
50. Envelope statistics of self-motion signals experienced by human subjects during everyday activities: Implications for vestibular processing
- Author
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Mohsen Jamali, Kathleen E. Cullen, Jerome Carriot, and Maurice J. Chacron
- Subjects
Male ,0301 basic medicine ,Velocity ,Motion Perception ,lcsh:Medicine ,Audiology ,Power law ,0302 clinical medicine ,Animal Cells ,Activities of Daily Living ,lcsh:Science ,Neurons ,Vestibular system ,Physics ,Coding Mechanisms ,Signal processing ,Multidisciplinary ,Classical Mechanics ,Signal Filtering ,Head Movements ,Physical Sciences ,Engineering and Technology ,Female ,Cellular Types ,Neural coding ,Research Article ,Adult ,medicine.medical_specialty ,Rotation ,Movement ,Acceleration ,Models, Neurological ,Stimulus (physiology) ,Motion ,Young Adult ,03 medical and health sciences ,Stimulus modality ,medicine ,Humans ,Motion perception ,Computational Neuroscience ,Behavior ,Afferent Pathways ,Quantitative Biology::Neurons and Cognition ,Proprioception ,Spectrum Analysis ,lcsh:R ,Biology and Life Sciences ,Computational Biology ,Afferent Neurons ,Cell Biology ,Probability Theory ,Probability Distribution ,030104 developmental biology ,Cellular Neuroscience ,Signal Processing ,lcsh:Q ,Neuroscience ,Mathematics ,030217 neurology & neurosurgery - Abstract
There is accumulating evidence that the brain's neural coding strategies are constrained by natural stimulus statistics. Here we investigated the statistics of the time varying envelope (i.e. a second-order stimulus attribute that is related to variance) of rotational and translational self-motion signals experienced by human subjects during everyday activities. We found that envelopes can reach large values across all six motion dimensions (~450 deg/s for rotations and ~4 G for translations). Unlike results obtained in other sensory modalities, the spectral power of envelope signals decreased slowly for low (< 2 Hz) and more sharply for high (>2 Hz) temporal frequencies and thus was not well-fit by a power law. We next compared the spectral properties of envelope signals resulting from active and passive self-motion, as well as those resulting from signals obtained when the subject is absent (i.e. external stimuli). Our data suggest that different mechanisms underlie deviation from scale invariance in rotational and translational self-motion envelopes. Specifically, active self-motion and filtering by the human body cause deviation from scale invariance primarily for translational and rotational envelope signals, respectively. Finally, we used well-established models in order to predict the responses of peripheral vestibular afferents to natural envelope stimuli. We found that irregular afferents responded more strongly to envelopes than their regular counterparts. Our findings have important consequences for understanding the coding strategies used by the vestibular system to process natural second-order self-motion signals.
- Published
- 2017
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