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Detecting the motion of an object relative to a world-fixed frame of reference is an exquisite human capability [G. E. Legge, F. Campbell, Vis. Res. 21 , 205-213 (1981)]. However, there is a special condition where humans are unable to accurately detect relative motion: Images moving in a direction consistent with retinal slip where the motion is unnaturally amplified can, under some conditions, appear stable [D. W. Arathorn, S. B. Stevenson, Q. Yang, P. Tiruveedhula, A. Roorda, J. Vis. 13 , 22 (2013)]. We asked: Is world-fixed retinal image background content necessary for the visual system to compute the direction of eye motion, and consequently generate stable percepts of images moving with amplified slip? Or, are nonvisual cues sufficient? Subjects adjusted the parameters of a stimulus moving in a random trajectory to match the perceived motion of images moving contingent to the retina. Experiments were done with and without retinal image background content. The perceived motion of stimuli moving with amplified retinal slip was suppressed in the presence of a visible background; however, higher magnitudes of motion were perceived under conditions when there was none. Our results demonstrate that the presence of retinal image background content is essential for the visual system to compute its direction of motion. The visual content that might be thought to provide a strong frame of reference to detect amplified retinal slips, instead paradoxically drives the misperception of relative motion., Competing Interests: Competing interests statement:P.T. and A.R. are co-inventors on US Patent #10130253, assigned to the University of California.

The target velocity at the retina and the initial phase of target motion are known to affect the perceived velocity of a target in planar motion. For depth motion, however, the role of this information in velocity perception remains unclear. Therefore, the purpose of this study was to reveal the role of the angular velocity derived from the vergence angle and the initial phase of target motion on the perceived velocity for depth motion. We devised two experimental tasks with five stimuli and used a two-alternative forced-choice paradigm to investigate velocity perception. In the tasks, a target moving toward or away from the observer was used. The five stimuli in each task moved between 40 and 240 cm (standard stimulus), 20 and 240 cm, 20 and 220 cm, 40 and 260 cm, and 60 and 260 cm from the participants. In the comparison of the standard stimulus with other stimuli, the stimuli approaching or receding from a distance of 20 cm were perceived as faster than the standard stimulus approaching or receding from a distance of 40 cm. We also showed that the stimuli that receded starting from a distance of 60 cm were perceived as moving slower than the standard stimulus. Our results suggest that larger changes in angular velocity affect velocity perception for depth motion; thus, observers perceive the target velocity as faster when the target is closer to the observer., Competing Interests: Declarations. Conflict of interest: The authors have no competing interests to declare that are relevant to the content of this article., (© 2024. The Author(s).)

To the microwave irradiation safety hazards caused by the co-construction of towers in smart grids, this paper investigates the effects of microwave irradiation in the power environment on the biological motion balance perception function. Firstly, simulation of microwave signals in the electric power environment, i.e., low-frequency harmonics and high-frequency carriers, were realized by signal modulation and applied in four types of behavior testing scenarios. Then, determining rats as target organisms to replace workers and randomly dividing into groups in proportion: open field, rotating rod fatigue, beam walking and forced swimming. Configuring radar with various parameters to match the electric power irradiation scene and stimulate rats, monitoring the abnormal behavior by image processing module, including posture, motion trajectory, distance, and other features. The experimental result showed that exposed to microwaves induce rats motor ability decline, balance perception imbalance, together with paralysis within long-term exposure, and its locomotor activity, coordination, posture control and reaction time all exhibit varying degrees of weakening. These findings indicate that microwave irradiation in electric power environment may pose significant health and safety risks for worker., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Human object perception depends on the proper integration of multiple visual features, such as color and motion. When features are integrated incorrectly, they are perceptually misbound and can cause illusions. This study investigates the phenomenon of continuous misbinding of color and motion features in peripheral vision, addressing the role of spatial continuity and color configuration in binding processes. Using a novel continuous report task, human subjects reported the perceived movement direction of color-coded dots in the peripheral visual field that were either congruent or incongruent with a foveal stimulus. Results indicate that spatial continuity is crucial for feature misbinding, with a marked decrease in peripheral perceptions bound to match foveal perception when the foveal and peripheral stimuli are spatially disjointed. Additionally, performance improved significantly when peripheral and foveal features were aligned, suggesting a 'positive illusion' effect where congruent features enhance perceptual accuracy. This effect was independent of the color pairings used, challenging the notion that color processing discrepancies might drive erroneous perception in this stimulus. These findings highlight the complex interplay between spatial configuration and perceptual accuracy in visual feature integration, with implications for understanding the neural basis of vision and developing applications to address perceptual inaccuracies in visual disorders., Competing Interests: Declarations Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Studies have shown that observers can accurately estimate the point-light walker (PLW) directions and bias their estimates towards the previous directions, exhibiting a serial dependence. Additionally, it has been demonstrated that the inversion of PLWs disrupts their global information and impairs the perception of certain attributes of PLWs. However, it remained unclear whether the global information of PLWs affected the estimation accuracy and serial dependence in the PLW direction estimation. In the current study, participants were presented with either a single or four PLW directions in each trial. In one condition, the PLW was upright; while in another condition, the PLW was inverted. Participants were asked to estimate the direction of the single PLW or the average direction of the four PLWs (i.e., ensemble direction), and each condition was finished by an independent group of participants. The results showed that the estimates of PLW directions were systematically compressed towards the reference direction (0°), showing a reference-attraction bias, and the inversion of the PLWs significantly decreased the estimation accuracy in the ensemble direction perception but not in the single direction perception. Moreover, a stronger serial dependence was observed when four PLWs were presented in previous trials as opposed to just one, and its magnitude was also reduced when the four PLWs were inverted. Therefore, the current study demonstrated the effects of global information on the estimation of PLW directions., Competing Interests: Declarations Competing interests The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In the motion-based stimulus-response compatibility (SRC) effect, responses are faster when the task-irrelevant stimulus motion is congruent with the response movement performance. In the present study, we tested whether smooth pursuit eye movements, related to tracking a moving object, influence motion-based SRC when present on their own or when combined with position-based SRC. We examined the motion-based SRC effect during both the response selection and response execution stages. When investigating motion-based SRC alone, participants responded with left or right movements of the single hand to the left or right movements of a centrally presented stimulus, either with their eyes fixated at the center or tracking the moving object. In the case of combined motion-based and position-based SRC, participants responded with left or right movements of the left or right hand to stimulus motion presented on the left or right side of the screen, again with eyes either fixated at the center or following the moving target. Results showed that during the response selection stage, smooth pursuit type eye movements had no effect on the motion-based SRC when the stimulus moved in the center, whereas the effect was enhanced when the stimulus presentation was lateralized. This aligns with the idea that attentional shifts differ between central and peripheral vision and that cognitive system computes various spatial maps for stimulus and response. In the case of response execution, smooth pursuit type eye movements had no effect on the motion-based SRC effect, regardless of stimulus location., Competing Interests: Declarations Competing interests The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Visual perceptual learning (VPL) refers to a long-term improvement of visual task performance through training or experience, reflecting brain plasticity even in adults. In human subjects, VPL has been mostly studied using functional magnetic resonance imaging (fMRI). However, due to the low temporal resolution of fMRI, how VPL affects the time course of visual information processing is largely unknown. To address this issue, we trained human subjects to perform a visual motion direction discrimination task. Their behavioral performance and magnetoencephalography (MEG) signals responding to the motion stimuli were measured before, immediately after, and two weeks after training. Training induced a long-lasting behavioral improvement for the trained direction. Based on the MEG signals from occipital sensors, we found that, for the trained motion direction, VPL increased the motion direction decoding accuracy, reduced the motion direction decoding latency, enhanced the direction-selective channel response, and narrowed the tuning profile. Following the MEG source reconstruction, we showed that VPL enhanced the cortical response in early visual cortex (EVC) and strengthened the feedforward connection from EVC to V3A. These VPL-induced neural changes co-occurred in 160-230 ms after stimulus onset. Complementary to previous fMRI findings on VPL, this study provides a comprehensive description on the neural mechanisms of visual motion perceptual learning from a temporal perspective and reveals how VPL shapes the time course of visual motion processing in the adult human brain., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024. Published by Elsevier Inc.)

Action video game (AVG) playing has been found to transfer to a variety of laboratory tasks in visual cognition. More recently, it has even been found to transfer to low-level visual "psychophysics tasks. This is unexpected since such low-level tasks have traditionally been found to be largely "immune" to transfer from another task, or even from the same task but a different stimulus attribute, e.g., motion direction. In this study, we set out to directly quantify transfer efficiency from AVG training to motion discrimination. Participants (n = 65) trained for 20 h on either a first-person active shooting video game, or a motion direction discrimination task with random dots. They were tested before, midway, and after training with the same motion task and an orientation discrimination task that had been shown to receive transfer from AVG training, but not from motion training. A subsequent control group (n = 18) was recruited to rule out any test-retest effect, by taking the same tests with the same time intervals, but without training. We found that improvement in motion discrimination performance was comparable between the AVG training and control groups, and less than the motion discrimination training group. We could not replicate the AVG transfer to orientation discrimination, but this was likely due to the fact that our participants were practically at chance for this task at all test points. Our study found no evidence, in either accuracy or reaction time, that AVG training transferred to motion discrimination. Overall, our results suggest that AVG training transferred little to lower-level visual skills, refining understanding of the mechanisms by which AVGs may affect vision. Protocol registration The accepted stage 1 protocol for this study can be found on the Open Science Framework at https://osf.io/zdv9c/?view_only=5b3b0c161dad448d9d1d8b14ce91ab11 . The stage 1 protocol for this Registered Report was accepted in principle on 01/12/22. The protocol, as accepted by the journal, can be found at: https://doi.org/10.17605/OSF.IO/ZDV9C., Competing Interests: Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Nonrigid forms of motion are commonplace in everyday life. Given previously documented age-related deteriorations in various tasks involving motion (discriminating speed, identifying motion direction, etc.), an experiment was conducted to evaluate the potential effect of age upon the visual ability to detect rigid and nonrigid object motion. Thirty younger and older observers participated in the experiment (mean ages were 19.9 and 75.8 years, respectively). As has been done multiple times in the past, the individual motions of object vertices were manipulated to simulate either rigid motion (rotation in depth, with or without precession) or two different types of nonrigid motion (also rotation in depth with or without precession, but with added object deformation). In confirmation of previous research, there were large effects of nonrigid motion type and precession upon the ability to differentiate between rigid and nonrigid object motion. There was also a large effect of age, such that the discrimination performance of the younger observers was 49.6% higher than that exhibited by the older observers. In this first ever study of aging and nonrigid object motion perception, we thus find that aging is associated with a substantial impairment in the ability to visually perceive object nonrigidity., Competing Interests: Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Motion provides a powerful sensory cue for segmenting a visual scene into objects and inferring the causal relationships between objects. Fundamental mechanisms involved in this process are the integration and segmentation of local motion signals. However, the computations that govern whether local motion signals are perceptually integrated or segmented remain unclear. Hierarchical Bayesian causal inference has recently been proposed as a model for these computations, yet a hallmark prediction of the model - its dependency on sensory uncertainty - has remained untested. We used a recently developed hierarchical stimulus configuration to measure how human subjects integrate or segment local motion signals while manipulating motion coherence to control sensory uncertainty. We found that (a) the perceptual transition from motion integration to segmentation shifts with sensory uncertainty, and (b) that perceptual variability is maximal around this transition point. Both findings were predicted by the model and challenge conventional interpretations of motion repulsion effects., Competing Interests: Declarations Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Polar angle asymmetries (PAAs), the differences in perceptual experiences and performance across different regions of the visual field are present in various paradigms and tasks of visual perception. Currently, research in this area is sparse, particularly regarding the influence of PAAs during perceptual illusions, highlighting a gap in visual cognition studies. We aim to fill this gap by measuring PAAs across the visual field during an illusion applied to test conscious vision widely. Motion-induced blindness (MIB) is an illusion when a peripheral target disappears from consciousness as the result of a continuously moving background pattern. During MIB we separately measured the average disappearance time of peripheral targets in eight equidistant visual field positions. Our results indicate a significant variation in MIB disappearance times and frequencies as a function of target location. Specifically, we found shorter and fewer disappearances along the cardinal compared to oblique directions, and along the horizontal compared to the vertical meridian. Our results suggest specific consistencies between visual field asymmetries and conscious visual perception., Competing Interests: Declarations Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Background: Previous studies have found that the temporal duration required for males to perceive visual motion direction is significantly shorter than that for females. However, the neural correlates of such shortened duration perception remain yet unclear. Given that motion perception is primarily associated with the neural activity of the middle temporal visual complex (MT+), we here test the novel hypothesis that the neural mechanism of these behavioral sex differences is mainly related to the MT+ region., Methods: We utilized ultra-high field (UHF) MRI to investigate sex differences in the MT+ brain region. A total of 95 subjects (48 females) participated in two separate studies. Cohort 1, consisting of 33 subjects (16 females), completed task-fMRI (drafting grating stimuli) experiment. Cohort 2, comprising 62 subjects (32 females), engaged in a psychophysical experiment measuring motion perception along different temporal thresholds as well as conducting structural and functional MRI scanning of MT+., Results: Our findings show pronounced sex differences in major brain parameters within the left MT+ (but not the right MT+, i.e., laterality). In particular, males demonstrate (i) larger gray matter volume (GMV) and higher brain's spontaneous activity at the fastest infra-slow frequency band in the left MT+; and (ii) stronger functional connectivity between the left MT+ and the left centromedial amygdala (CM). Meanwhile, both female and male participants exhibited comparable correlations between motion perception ability and the multimodal imaging indexes of the MT+ region, i.e., larger GMV, higher brain's spontaneous activity, and faster motion discrimination., Conclusions: Our findings reveal sex differences of imaging indicators of structure and function in the MT+ region, which also relate to the temporal threshold of motion discrimination. Overall, these results show how behavioral sex differences in visual motion perception are generated, and advocate considering sex as a crucial biological variable in both human brain and behavioral research., Competing Interests: Declarations Ethics approval and consent to participate All procedures were approved by the Ethics Review Committee of Zhejiang University, and conducted in accordance with the Helsinki Declaration. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Vision generates a stable representation of space by combining retinal input with internal predictions about the visual consequences of eye movements. We report a type of nonrigid motion that disrupts the connection between eye movements and perception, causing visual instability. This motion is accurately perceived during fixation, but it cannot be pursued. Catch-up saccades are accurately directed to the moving target but the motion stimulus appears to jump in space with each saccade. Our results reveal four major findings about perception and the visuomotor system: (i) Pursuit fails for certain types of motion; (ii) pursuit and catch-up saccades are independently controlled; (iii) prediction of saccade consequences is independent from saccade control; and (iv) the visual stability of moving objects relies on similar motion mechanisms as pursuit.

Most vertebrates, including humans, are highly adept at detecting and encoding biological motion, even when it is portrayed by just a few point lights attached to the head and major joints. However, the function of subcortical regions in biological motion perception has been scarcely explored. Here, we investigate the role of the superior colliculus in local biological motion processing. Using high-field (3 T) and ultra-high-field (7 T) functional magnetic resonance imaging, we record the neural responses of the superior colliculus to scrambled point-light walkers (with local kinematics retained) in both humans and male macaque monkeys. Results show that the superior colliculus, especially the superficial layers, selectively responds to local biological motion. Furthermore, dynamic causal modeling analysis reveals a subcortical-cortical functional pathway that transmits local biological motion signals from the superior colliculus via the middle temporal visual complex to the posterior superior temporal sulcus in the human brain. These findings suggest the existence of a cross-species mechanism in the superior colliculus that facilitates the detection of local biological motion at the early stage of the visual processing stream., (© 2024. The Author(s).)

When catching a falling ball or avoiding a collision with traffic, humans can quickly generate eye and limb responses to unpredictable changes in their environment. Mechanisms of limb and oculomotor control when responding to sudden changes in the environment have mostly been investigated independently. Here, we investigated eye-hand coordination in a rapid interception task where human participants used a virtual paddle to intercept a moving target. The target moved vertically down a computer screen and could suddenly jump to the left or right. In high-certainty blocks, the target always jumped; in low-certainty blocks, the target only jumped in a portion of the trials. Further, we manipulated response urgency by varying the time of target jumps, with early jumps requiring less urgent responses and late jumps requiring more urgent responses. Our results highlight differential effects of certainty and urgency on eye-hand coordination. Participants initiated both eye and hand responses earlier for high-certainty compared with low-certainty blocks. Hand reaction times decreased and response vigor increased with increasing urgency levels. However, eye reaction times were lowest for medium-urgency levels and eye vigor was unaffected by urgency. Across all trials, we found a weak positive correlation between eye and hand responses. Taken together, these results suggest that the limb and oculomotor systems use similar early sensorimotor processing; however, rapid responses are modulated differentially to attain system-specific sensorimotor goals.

Visual features need to be temporally integrated to detect motion signals and solve the many ill-posed problems of vision. It has previously been shown that such integration occurs in windows of unconscious processing of up to 450 milliseconds. However, whether features are integrated should be governed by perceptually meaningful mechanisms. Here, we expand on previous findings suggesting that subjective perception and integration may be linked. Specifically, different observers were found to group elements differently and to exhibit corresponding feature integration behavior. If the former were to influence the latter, perception would appear to not only be the outcome of integration but to potentially also be part of it. To test any such linkages more systematically, we here examined the role of one of the key perceptual grouping cues, color similarity, in the Sequential Metacontrast Paradigm (SQM). In the SQM, participants are presented with two streams of lines that are expanding from the center outwards. If several lines in the attended motion stream are offset, offsets integrate unconsciously and mandatorily for periods of up to 450 milliseconds. Across three experiments, we presented lines of varied colors. Our results reveal that individuals who perceive differently colored lines as "popping out" from the motion stream do not exhibit mandatory integration but that individuals who perceive such lines as part of an integrated motion stream do show offset integration behavior across the entire stream. These results attest to the proposed linkage between subjective perception and integration behavior in the SQM.

Serial dependence effects have been observed across a wide range of perceptual and oculomotor tasks. This opens up the question of whether these effects observed share underlying mechanisms. Here we measured serial dependence effects in a semipredictable environment for the same group of observers across four different tasks, two perceptual (color and orientation judgments) and two oculomotor (tracking moving targets and the pupil light reflex). By leveraging individual differences, we searched for links in the magnitude of serial dependence effects across the different tasks. On the group level, we observed significant attractive serial dependence effects for all tasks, except the pupil response. The rare absence of a serial dependence effect for the reflex-like pupil light response suggests that sequential effects require cortical processing or even higher-level cognition. For the tasks with significant serial dependence effects, there was substantial and reliable variance in the magnitude of the sequential effects. We observed a significant relationship in the strength of serial dependence for the two perceptual tasks, but no relation between the perceptual tasks and oculomotor tracking. This emphasizes differences in processing between perception and oculomotor control. The lack of a correlation across all tasks indicates that it is unlikely that the relation between the individual differences in the magnitude of serial dependence is driven by more general mechanisms related to for example working memory. It suggests that there are other shared perceptual or decisional mechanisms for serial dependence effects across different low-level perceptual tasks.

For the brain to compute object motion in the world during self-motion, it must discount the global patterns of image motion (optic flow) caused by self-motion. Optic flow parsing is a proposed visual mechanism for computing object motion in the world, and studies in both humans and monkeys have demonstrated perceptual biases consistent with the operation of a flow-parsing mechanism. However, the neural basis of flow parsing remains unknown. We demonstrate, at both the individual unit and population levels, that neural activity in macaque middle temporal (MT) area is biased by peripheral optic flow in a manner that can at least partially account for perceptual biases induced by flow parsing. These effects cannot be explained by conventional surround suppression mechanisms or choice-related activity and have substantial neural latency. Together, our findings establish the first neural basis for the computation of scene-relative object motion based on flow parsing., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

This study investigated whether infants encode better the features of a briefly occluded object if its movements are specified simultaneously by vision and audition than if they are not (data collected: 2017-2019). Experiment 1 showed that 10-month-old infants (N = 39, 22 females, White-English) notice changes in the visual pattern on the object irrespective of the stimulation received (spatiotemporally congruent audio-visual stimulation, incongruent stimulation, or visual-only; η p 2  = .53). Experiment 2 (N = 72, 36 female) found similar results in 6-month-olds (Test Block 1, η p 2  = .13), but not 4-month-olds. Experiment 3 replicated this finding with another group of 6-month-olds (N = 42, 21 females) and showed that congruent stimulation enables infants to detect changes in object trajectory (d = 0.56) in addition to object pattern (d = 1.15), whereas incongruent stimulation hinders performance., (© 2024 The Author(s). Child Development © 2024 Society for Research in Child Development.)

In healthy vision, bright slow-motion stimuli are processed primarily by the regions of the visual system that receive input from the central part of the scene, whereas processing of dark fast-motion stimuli is more dependent on peripheral visual input. We tested 31 retinitis pigmentosa (RP) patients with long-term loss of peripheral photoreceptors and healthy controls with temporarily limited peripheral vision. We measured motion-based acuity using random-dot kinematograms, establishing individual thresholds for differentiating a circle from an ellipse. Participants subsequently performed a functional magnetic resonance imaging (fMRI) task set at a constant level of difficulty. The results showed that limiting vision did not affect motion-acuity thresholds in control participants but did cause different brain activations than those in RP patients, indicating prompt implementation of the strategy that would be perceptually successful. Compared with controls with both full and limited vision, impaired motion acuity in RP patients led to decreased brain activation, particularly in the primary peripheral visual areas V1-3. Importantly, compared with controls in full vision, matched decreased activation in MT+/V5, salience-processing cortices and the superior temporal cortex were detected in RP patients and in controls with limited peripheral vision, revealing brain networks that compensate for the loss of peripheral vision., (© 2024. The Author(s).)

A key feature of the receptive field of neurons in the visual system is their centre-surround antagonism, whereby the centre and the surround exhibit responses of opposite polarity. This organization is thought to enhance visual acuity, but whether and how such antagonism plays a role in more complex processing remains poorly understood. Here, we investigate the role of centre and surround receptive fields in retinal direction selectivity by exposing posterior-preferring On-Off direction-selective ganglion cells (pDSGCs) to adaptive light and recording their response to globally moving objects. We reveal that light adaptation leads to surround expansion in pDSGCs. The pDSGCs maintain their original directional tuning in the centre receptive field, but present the oppositely tuned response in their surround. Notably, although inhibition is the main substrate for retinal direction selectivity, we found that following light adaptation, both the centre- and surround-mediated responses originate from directionally tuned excitatory inputs. Multi-electrode array recordings show similar oppositely tuned responses in other DSGC subtypes. Together, these data attribute a new role for excitation in the direction-selective circuit. This excitation carries an antagonistic centre-surround property, possibly designed to sharpen the detection of motion direction in the retina. KEY POINTS: Receptive fields of direction-selective retinal ganglion cells expand asymmetrically following light adaptation. The increase in the surround receptive field generates a delayed spiking phase that is tuned to the null direction and is mediated by excitation. Following light adaptation, excitation rules the computation in the centre receptive field and is tuned to the preferred direction. GABAergic and glycinergic inputs modulate the null-tuned delayed response differentially. Null-tuned delayed spiking phases can be detected in all types of direction-selective retinal ganglion cells. Light adaptation exposes a hidden directional excitation in the circuit, which is tuned to opposite directions in the centre and surround receptive fields., (© 2024 The Author(s). The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

Humans appear to be endowed with the ability to readily share attention with interactive partners through the utilization of social direction cues, such as eye gaze and biological motion (BM). Here, we investigated the specialized brain mechanism underlying this fundamental social attention ability by incorporating different types of social (i.e., BM, gaze) and non-social (arrow) cues and combining functional magnetic resonance imaging (fMRI) with a modified central cueing paradigm. Using multi-voxel pattern analysis (MVPA), we found that although gaze- and BM-mediated attentional orienting could be decoded from neural activity in a wide range of brain areas, only the right anterior and posterior superior temporal sulcus (aSTS and pSTS) could specifically decode attentional orienting triggered by social but not non-social cues. Critically, cross-category MVPA further revealed that social attention could be decoded across BM and gaze cues in the right STS and the right superior temporal gyrus (STG). However, these regions could not decode attentional orienting across social and non-social cues. These findings together provide evidence for the existence of a specialized social attention module in the human brain, with the right STS/STG being the critical neural site dedicated to social attention., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Path integration, the process of updating one's position using successive self-motion signals, has previously been studied with visual distance reproduction tasks in which optic flow patterns provide information about traveled distance. These studies have reported that reproduced distances show two types of systematic biases: central tendency and serial dependence. In the present study, we investigated whether these biases are also present in vestibular path integration. Participants were seated on a linear motion platform and performed a distance reproduction task in total darkness. The platform first passively moved the participant a predefined stimulus distance, which they then actively reproduced by steering the platform back the same distance. Stimulus distances were sampled from short- and long-distance probability distributions and presented either in a randomized order or in separate blocks to study the effect of presentation context. Similar to the effects observed in visual path integration, we found that reproduced distances showed an overall positive central tendency effect as well as a positive, attractive serial dependence effect. Furthermore, reproduction behavior was affected by presentation context. These results were mostly consistent with predictions of a Bayesian Kalman filter model, originally proposed for visual path integration. NEW & NOTEWORTHY Distance reproduction tasks based on visual information about the traveled distance have shown that reproductions are biased by central tendency and serial dependence effects. Here, we show that distance reproductions based on vestibular signals show similar biases and that the reproductions are affected by the presentation order of the stimulus distances.

Our current perception and decision-making are shaped by recent experiences, a phenomenon known as serial dependence. While serial dependence is well-documented in visual perception and has been recently explored in time perception, their functional similarities across non-temporal and temporal domains remain elusive, particularly in relation to task relevance and working memory load. To address this, we designed a unified experimental paradigm using coherent motion stimuli to test both direction and time reproduction. The direction and time tasks were randomly mixed across trials. Additionally, we introduced pre-cue versus post-cue settings in separate experiments to manipulate working memory load during the encoding phase. We found attractive biases in time reproduction but repulsive biases in direction estimation. Notably, the temporal attraction was more pronounced when the preceding task was also time-related. In contrast, the direction repulsion remained unaffected by the nature of the preceding task. Additionally, both attractive and repulsive biases were enhanced by the post-cue compared to the pre-cue. Our findings suggest that opposing sequential effects in non-temporal and temporal domains may originate from different processing stages linked to sensory adaptation and post-perceptual processes involving working memory., (© 2024 The Author(s). British Journal of Psychology published by John Wiley & Sons Ltd on behalf of The British Psychological Society.)

Representational momentum (RM) refers to the phenomenon in which an observer's judgment of the final location of a previously viewed moving target is often displaced forward in the direction of motion. This phenomenon is an adaptive mechanism that compensates for neural processing delays and is closely associated with visual cortex function. However, the impact of age-related decline of visual cortex function on the manifestations of RM remains unclear. The present study examined differences in the RM effect between older ( N = 82) and younger adults ( N = 74) using a cursor-positioning task. Additionally, resting-state functional magnetic resonance imaging was used to explore the potential neural substrates that underlie these differences, employing amplitude of low-frequency fluctuation (ALFF, reflecting the intensity of neural activity) and regional homogeneity (ReHo, reflecting the synchronization of neural activity) as indicators. Our findings indicate a significant increase in RM among older adults compared with younger adults. Neuroimaging data revealed a significant decrease in ALFF and ReHo within extensive regions of the visual cortex in older adults, validating age-related differences in this cortical area. More importantly, ALFF values in the bilateral visual area 3 and ReHo values in the bilateral visual area 2 in older adults exhibited a strong negative correlation with their RM effects. These results suggest that larger RM in older adults may be functional compensation for aging of the visual cortex. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

There are primarily two classes of bio-inspired looming perception visual systems. The first class employs hierarchical neural networks inspired by well-acknowledged anatomical pathways responsible for looming perception, and the second maps nonlinear relationships between physical stimulus attributes and neuronal activity. However, even with multi-layered structures, the former class is sometimes fragile in looming selectivity, i.e., the ability to well discriminate between approaching and other categories of movements. While the latter class leaves qualms regarding how to encode visual movements to indicate physical attributes like angular velocity/size. Beyond those, we propose a novel looming perception model based on dynamic neural field (DNF). The DNF is a brain-inspired framework that incorporates both lateral excitation and inhibition within the field through instant feedback, it could be an easily-built model to fulfill the looming sensitivity observed in biological visual systems. To achieve our target of looming perception with computational efficiency, we introduce a single-field DNF with adaptive lateral interactions and dynamic activation threshold. The former mechanism creates antagonism to translating motion, and the latter suppresses excitation during receding. Accordingly, the proposed model exhibits the strongest response to moving objects signaling approaching over other types of external stimuli. The effectiveness of the proposed model is supported by relevant mathematical analysis and ablation study. The computational efficiency and robustness of the model are verified through systematic experiments including on-line collision-detection tasks in micro-mobile robots, at success rate of 93% compared with state-of-the-art methods. The results demonstrate its superiority over the model-based methods concerning looming perception., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Significant progress has been achieved in multi-object tracking (MOT) through the evolution of detection and re-identification (ReID) techniques. Despite these advancements, accurately tracking objects in scenarios with homogeneous appearance and heterogeneous motion remains a challenge. This challenge arises from two main factors: the insufficient discriminability of ReID features and the predominant utilization of linear motion models in MOT. In this context, we introduce a novel motion-based tracker, MotionTrack, centered around a learnable motion predictor that relies solely on object trajectory information. This predictor comprehensively integrates two levels of granularity in motion features to enhance the modeling of temporal dynamics and facilitate precise future motion prediction for individual objects. Specifically, the proposed approach adopts a self-attention mechanism to capture token-level information and a Dynamic MLP layer to model channel-level features. MotionTrack is a simple, online tracking approach. Our experimental results demonstrate that MotionTrack yields state-of-the-art performance on datasets such as Dancetrack and SportsMOT, characterized by highly complex object motion., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Self-supervised contrastive learning draws on power representational models to acquire generic semantic features from unlabeled data, and the key to training such models lies in how accurately to track motion features. Previous video contrastive learning methods have extensively used spatially or temporally augmentation as similar instances, resulting in models that are more likely to learn static backgrounds than motion features. To alleviate the background shortcuts, in this paper, we propose a cross-view motion consistent (CVMC) self-supervised video inter-intra contrastive model to focus on the learning of local details and long-term temporal relationships. Specifically, we first extract the dynamic features of consecutive video snippets and then align these features based on multi-view motion consistency. Meanwhile, we compare the optimized dynamic features for instance comparison of different videos and local spatial fine-grained with temporal order in the same video, respectively. Ultimately, the joint optimization of spatio-temporal alignment and motion discrimination effectively fills the challenges of the missing components of instance recognition, spatial compactness, and temporal perception in self-supervised learning. Experimental results show that our proposed self-supervised model can effectively learn visual representation information and achieve highly competitive performance compared to other state-of-the-art methods in both action recognition and video retrieval tasks., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Self vs. external attribution of motions based on vestibular cues is suggested to underlie our coherent perception of object motion and self-motion. However, it remains unclear whether such attribution also underlies sensorimotor responses. Here, we examined this issue in the context of touch. We asked participants to lightly touch a moving object with their thumb while standing still on an unstable surface. We measured both the accuracy of judging the object motion direction and the postural response. If the attribution underlies both object-motion perception and posture control, sensitivity of posture to object motion should decrease with motion speed since high speed motion is unlikely to reflect self-motion. Furthermore, when motion perception is erroneous, there should be a corresponding increase in postural responses. Our results are consistent with these predictions and suggest that self-external attribution of somatosensory motion underlies both object motion perception and postural responses., (© 2024. The Author(s).)

Neurobiological investigations of perceptual decision-making have furnished the first glimpse of a flexible cognitive process at the level of single neurons. Neurons in the parietal and prefrontal cortex are thought to represent the accumulation of noisy evidence, acquired over time, leading to a decision. Neural recordings averaged over many decisions have provided support for the deterministic rise in activity to a termination bound. Critically, it is the unobserved stochastic component that is thought to confer variability in both choice and decision time. Here, we elucidate this drift-diffusion signal on individual decisions. We recorded simultaneously from hundreds of neurons in the lateral intraparietal cortex of monkeys while they made decisions about the direction of random dot motion. We show that a single scalar quantity, derived from the weighted sum of the population activity, represents a combination of deterministic drift and stochastic diffusion. Moreover, we provide direct support for the hypothesis that this drift-diffusion signal approximates the quantity responsible for the variability in choice and reaction times. The population-derived signals rely on a small subset of neurons with response fields that overlap the choice targets. These neurons represent the integral of noisy evidence. Another subset of direction-selective neurons with response fields that overlap the motion stimulus appear to represent the integrand. This parsimonious architecture would escape detection by state-space analyses, absent a clear hypothesis., Competing Interests: NS, GS, ET, AZ, MS No competing interests declared, DW consultant to CTRL- Labs Inc, in the Reality Labs Division of Meta. This entity did not support or influence this work, (© 2023, Steinemann, Stine et al.)

Perceiving emotions from the movements of other biological entities is critical for human survival and interpersonal interactions. Here, we report that emotional information conveyed by point-light biological motion (BM) triggered automatic physiological responses as reflected in pupil size. Specifically, happy BM evoked larger pupil size than neutral and sad BM, while sad BM induced a smaller pupil response than neutral BM. Moreover, this happy over sad pupil dilation effect is negatively correlated with individual autistic traits. Notably, emotional BM with only local motion features retained could also exert modulations on pupils. Compared with intact BM, both happy and sad local BM evoked stronger pupil responses than neutral local BM starting from an earlier time point, with no difference between the happy and sad conditions. These results revealed a fine-grained pupil-related emotional modulation induced by intact BM and a coarse but rapid modulation by local BM, demonstrating multi-level processing of emotions in life motion signals. Taken together, our findings shed new light on BM emotion processing, and highlight the potential of utilizing the emotion-modulated pupil response to facilitate the diagnosis of social cognitive disorders., Competing Interests: TY, LW, YJ No competing interests declared, (© 2023, Yuan et al.)

Animals rely on compensatory actions to maintain stability and navigate their environment efficiently. These actions depend on global visual motion cues known as optic-flow. While the optomotor response has been the traditional focus for studying optic-flow compensation in insects, its simplicity has been insufficient to determine the role of the intricate optic-flow processing network involved in visual course control. Here, we reveal a series of course control behaviours in Drosophila and link them to specific neural circuits. We show that bilateral electrical coupling of optic-flow-sensitive neurons in the fly's lobula plate are required for a proper course control. This electrical interaction works alongside chemical synapses within the HS-H2 network to control the dynamics and direction of turning behaviours. Our findings reveal how insects use bilateral motion cues for navigation, assigning a new functional significance to the HS-H2 network and suggesting a previously unknown role for gap junctions in non-linear operations., (© 2024. The Author(s).)

It is a well-established finding that more informative optic flow (e.g., faster, denser, or presented over a larger portion of the visual field) yields decreased variability in heading judgements. Current models of heading perception further predict faster processing under such circumstances, which has, however, not been supported empirically so far. In this study, we validate a novel continuous psychophysics paradigm by replicating the effect of the speed and density of optic flow on variability in performance, and we investigate how these manipulations affect the temporal dynamics. To this end, we tested 30 participants in a continuous psychophysics paradigm administered in Virtual Reality. We immersed them in a simple virtual environment where they experienced four 90-second blocks of optic flow where their linear heading direction (no simulated rotation) at any given moment was determined by a random walk. We asked them to continuously indicate with a joystick the direction in which they perceived themselves to be moving. In each of the four blocks they experienced a different combination of simulated self-motion speeds (SLOW and FAST) and density of optic flow (SPARSE and DENSE). Using a Cross-Correlogram Analysis, we determined that participants reacted faster and displayed lower variability in their performance in the FAST and DENSE conditions than in the SLOW and SPARSE conditions, respectively. Using a Kalman Filter-based analysis approach, we found a similar pattern, where the fitted perceptual noise parameters were higher for SLOW and SPARSE. While replicating previous results on variability, we show that more informative optic flow can speed up heading judgements, while at the same time validating a continuous psychophysics as an efficient method for studying heading perception., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Jörges 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.)

The perception of an object's location is profoundly influenced by the surrounding dynamics. This is dramatically demonstrated by the frame effect, where a moving frame induces substantial shifts in the perceived location of objects that flash within it. In this study, we examined the elements contributing to the large magnitude of this effect. Across three experiments, we manipulated the number of probes, the dynamics of the frame, and the spatiotemporal relationships between probes and the frame. We found that the presence of multiple probes amplified the position shift, whereas the accumulation of the frame effect over repeated motion cycles was minimal. Notably, an oscillating frame generated more pronounced effects compared to a unidirectional moving frame. Furthermore, the spatiotemporal distance between the frame and the probe played pivotal roles, with larger shifts observed near the leading edge of the frame. Interestingly, although larger frames produced stronger position shifts, the maximum shift occurred almost at the same distance relative to the frame's center across all tested sizes. Our findings suggest that the number of probes, frame size, relative probe-frame distance, and frame dynamics collectively contribute to the magnitude of the position shift.

Visual illusions are systematic misperceptions that can help us glean the heuristics with which the brain constructs visual experience. In a recently discovered visual illusion (the "frame effect"), it has been shown that flashing a stimulus inside of a moving frame produces a large misperception of that stimulus's position. Across two experiments, we investigated a novel illusion (the "split stimulus effect") where the symmetrical motion of two overlaid frames produces two simultaneous positional misperceptions of a single stimulus. That is, one stimulus is presented but two are perceived. In both experiments, a single red dot was flashed when the moving frames reversed direction, and participants were asked to report how many dots they saw. Naïve participants sometimes reported seeing two dots when only one was presented, indicating spontaneous perception of the illusion. A Bayesian analysis of the population prevalence of this effect was conducted. The dependence of this effect on the frames' speed, the dot's opacity, spatial attention, as the presence/absence of pre-flash motion ("postdiction") was also investigated, and the features of this illusion were compared to similar motion position illusions within a predictive processing framework. In demonstrating this illusory "splitting" effect, this study is the first to show that it is possible to be simultaneously aware of two opposing perceptual predictions about a single object and provides evidence of the hyperpriors that limit and inform the structure of visual experience.

Falling objects are commonplace in daily life, requiring precise perceptual judgments for interception and avoidance. We argue that human judgments of projectile motion arise from the interplay between sensory information and predictions constrained by Newtonian mechanics. Our study investigates how individuals perceive falling objects under various gravitational conditions, aiming to understand the role of internalized gravity in visual perception. Through meticulously controlling the available information, we demonstrated that these phenomena cannot be explained solely by simple heuristics nor representational momentum. Instead, we found that the perceptual judgments of humans (n = 11, 13, 14, and 11, respectively, in Experiments 1, 2, 3, and 4) are influenced by a combination of sensory information and gravity predictions, highlighting the role of internalized physical constraints in the perception of projectile motion.

Motion vision is vital for a wide range of animal behaviors. Fiddler crabs, for example, rely heavily on motion to detect the movement of avian predators. They are known to detect first-order motion using both intensity (defined by spatiotemporal correlations in luminance) and polarization information (defined separately as spatiotemporal correlations in the degree and/or angle of polarization). However, little is known about their ability to detect second-order motion, another important form of motion information; defined separately by spatiotemporal correlations in higher-order image properties. In this work we used behavioral experiments to test how fiddler crabs (Afruca tangeri) responded to both second-order intensity and polarization stimuli. Fiddler crabs responded to a number of different intensity based second-order stimuli. Furthermore, the crabs also responded to second-order polarization stimuli, a behaviorally relevant stimulus applicable to an unpolarized flying bird when viewed against a polarized sky. The detection of second-order motion in polarization is, to the best of our knowledge, the first demonstration of this ability in any animal. This discovery therefore opens a new dimension in our understanding of how animals use polarization vision for target detection and the broader importance of second-order motion detection for animal behavior., (© 2024. The Author(s).)

Our senses are constantly exposed to external stimulation. Part of the sensory stimulation is produced by our own movement, like visual motion on the retina or tactile sensations from touch. Sensations caused by our movements appear attenuated. The interpretation of current stimuli is influenced by previous experiences, known as serial dependencies. Here we investigated how sensory attenuation and serial dependencies interact. In Experiment 1, we showed that temporal predictability causes sensory attenuation. In Experiment 2, we isolated temporal predictability in a visuospatial localization task. Attenuated stimuli are influenced by serial dependencies. However, the magnitude of the serial dependence effects varies, with greater effects when the certainty of the previous trial is equal to or greater than the current one. Experiment 3 examined sensory attenuation's influence on serial dependencies. Participants localized a briefly flashed stimulus after pressing a button (self-generated) or without pressing a button (externally generated). Stronger serial dependencies occurred in self-generated trials compared to externally generated ones when presented alternately but not when presented in blocks. We conclude that the relative uncertainty in stimulation between trials determines serial dependency strengths.

Purpose: The purpose of this study was to investigate the short- and long-term learning effect of dynamic visual acuity (DVA) tests., Methods: Participants between 18 and 30 years with corrected to normal visual acuity were enrolled in this study. Three repeated sessions were performed, with 15 minutes and 15 days' intervals between sessions. Each session included 9 DVA tests of horizontal, vertical, and diagonal motions of E optotypes at 20, 40, and 80 degrees per second (dps). The short- and long-term learning effects were analyzed from repeated DVA tests., Results: Of the 58 enrolled participants, the mean age was 23.1 ± 2.1 years. DVA significantly varied among motion types and velocities (P < 0.05, respectively). There was a significant short-term learning effect for 20 (P = 0.004), 40 (P < 0.001), and 80 (P = 0.014) dps DVA test of horizontal motion, 40 dps DVA test of vertical (P = 0.003), and diagonal motion (P = 0.036). The long-term learning effect was detected in the 40 dps diagonal motion DVA test (P = 0.015). The short- and long-term learning effects were positively associated with initial DVA in most combinations of motion type and velocity tests (P < 0.05, respectively). The short- (P = 0.031) and long-term (P = 0.024) learning effect of 80 dps horizontal motion DVA test was greater in male than female participants., Conclusions: There is a significant short-term learning effect in the DVA test of various motion types, but the long-term learning effect was rarely observed, and it is greater in participants with worse initial DVA.

This study investigates how American Sign Language (ASL) fluency and hearing status influence the perception of biological motion, using three point-light display (PLD) tasks. Prior research indicates that early exposure to ASL among deaf signers results in more rapid and effortless recognition of biological motion than hearing nonsigners, potentially due to the expertise in deciphering complex human movements or possibly due to neuroplasticity in deaf brains. However, it remains uncertain whether this advantage stems from signed language proficiency or the experience of being deaf. To explore this, we designed three PLD tasks involving viewing randomly moving dots, identifying a person from biological motion PLDs, and determining whether right-side up and inverted PLDs depict actions involving a ball. A diverse cohort of participants (N = 224) with varying ASL fluencies and hearing statuses completed the tasks online, providing us with reaction time and accuracy data. Our results demonstrate that earlier ASL exposure is associated with accuracy, especially on complex action identification tasks. Furthermore, we discovered robust evidence for a speed-accuracy trade-off in deaf participants, in which they performed more quickly but less accurately. The speed-accuracy trade-off was evident in the most difficult task, the action identification task. Further analysis of this deaf group revealed that earlier signed language acquisition led to higher accuracy in action identification task. We conclude that age of ASL exposure and hearing status both significantly contribute to variations in biological motion perception, with implications for understanding visual expertise and cognitive processing in both deaf and signing populations. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

A catalogue of neuronal cell types has often been called a 'parts list' of the brain 1 , and regarded as a prerequisite for understanding brain function 2,3 . In the optic lobe of Drosophila, rules of connectivity between cell types have already proven to be essential for understanding fly vision 4,5 . Here we analyse the fly connectome to complete the list of cell types intrinsic to the optic lobe, as well as the rules governing their connectivity. Most new cell types contain 10 to 100 cells, and integrate information over medium distances in the visual field. Some existing type families (Tm, Li, and LPi) 6-10 at least double in number of types. A new serpentine medulla (Sm) interneuron family contains more types than any other. Three families of cross-neuropil types are revealed. The consistency of types is demonstrated by analysing the distances in high-dimensional feature space, and is further validated by algorithms that select small subsets of discriminative features. We use connectivity to hypothesize about the functional roles of cell types in motion, object and colour vision. Connectivity with 'boundary types' that straddle the optic lobe and central brain is also quantified. We showcase the advantages of connectomic cell typing: complete and unbiased sampling, a rich array of features based on connectivity and reduction of the connectome to a substantially simpler wiring diagram of cell types, with immediate relevance for brain function and development., (© 2024. The Author(s).)

Aims: To assess whether impaired vestibular perception of self-motion is a risk factor for unsteadiness and falls in elderly patients with type 2 diabetes (T2D)., Materials and Methods: 113 participants (65-75 years old) with T2D underwent tests of roll and pitch discrimination, postural stability (Berg Balance Scale, Modified Romberg Test, and quantitative posturography), clinical examination and blood chemistry analyses. Falls 1-year after enrolment were self-reported. We performed cluster analysis based on the values of the vestibular motion thresholds, and logistic stepwise regression to compare the clinical-biochemical parameters between clusters., Results: We identified two clusters (VC1 n = 65 and VC2 n = 48 participants). VC2 had significantly (p < 0.001) higher (poorer) thresholds than VC1: mean pitch threshold 1.62°/s (95% CI 1.48-1.78) in VC2 and 0.91°/s (95% CI 0.84-0.98) in VC1, mean roll threshold 1.34°/s (95% CI 1.21-1.48) in VC2 and 0.69°/s (95% CI 0.64-0.74) in VC1. Diabetes duration was significantly (p = 0.024) longer in VC2 (11.96 years, 95% CI 9.23-14.68) than in VC1 (8.37 years, 95% CI 6.85-9.88). Glycaemic control was significantly (p = 0.014) poorer in VC2 (mean HbA1c 6.74%, 95% CI 6.47-7.06) than in VC1 (mean HbA1c 6.34%, 95% CI 6.16-6.53). VC2 had a significantly higher incidence of postural instability than VC1, with a higher risk of failing the Modified Romberg Test C4 (RR = 1.57, χ 2  = 5.33, p = 0.021), reporting falls during follow-up (RR = 11.48, χ 2  = 9.40, p = 0.002), and greater postural sway in the medio-lateral direction (p < 0.025)., Conclusions: Assessing vestibular motion thresholds identifies individuals with T2D at risk of postural instability due to altered motion perception and guides vestibular rehabilitation., (© 2024 The Author(s). Diabetes/Metabolism Research and Reviews published by John Wiley & Sons Ltd.)

We can now measure the connectivity of every neuron in a neural circuit 1-9 , but we cannot measure other biological details, including the dynamical characteristics of each neuron. The degree to which measurements of connectivity alone can inform the understanding of neural computation is an open question 10 . Here we show that with experimental measurements of only the connectivity of a biological neural network, we can predict the neural activity underlying a specified neural computation. We constructed a model neural network with the experimentally determined connectivity for 64 cell types in the motion pathways of the fruit fly optic lobe 1-5 but with unknown parameters for the single-neuron and single-synapse properties. We then optimized the values of these unknown parameters using techniques from deep learning 11 , to allow the model network to detect visual motion 12 . Our mechanistic model makes detailed, experimentally testable predictions for each neuron in the connectome. We found that model predictions agreed with experimental measurements of neural activity across 26 studies. Our work demonstrates a strategy for generating detailed hypotheses about the mechanisms of neural circuit function from connectivity measurements. We show that this strategy is more likely to be successful when neurons are sparsely connected-a universally observed feature of biological neural networks across species and brain regions., (© 2024. The Author(s).)

We showed to the same observers both dynamic and static 2D patterns that can both evoke distinctive perceptions of motion or optic flow, as if moving in a tunnel or into a dark hole. At all times pupil diameters were monitored with an infrared eye tracker. We found a converging set of results indicating stronger pupil dilations to expansive growth of shapes or optic flows evoking a forward motion into a dark tunnel. Multiple regression analyses showed that the pupil responses to the illusory expanding black holes of static patterns were predicted by the individuals' pupil response to optic flows showing spiraling motion or "free fall" into a black hole. Also, individuals' pupil responses to spiraling motion into dark tunnels predicted the individuals' sense of illusory expansion with the static, illusory expanding, dark holes. This correspondence across individuals between their pupil responses to both dynamic and static, illusory expanding, holes suggests that these percepts reflect a common perceptual mechanism, deriving motion from 2D scenes, and that the observers' pupil adjustments reflect the direction and strength of motion they perceive and the expected outcome of an increase in darkness., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: The perception of biological motion requires accurate prediction of the spatiotemporal dynamics of human movement. Research on Developmental Coordination Disorder (DCD) suggests deficits in accurate motor prediction, raising the question whether not just action execution, but also action perception is perturbed in this disorder., Aims: To examine action perception by comparing the neural response to the observation of apparent biological motion in children with and without DCD., Methods and Procedures: Thirty-three participants with and 33 without DCD, matched based on age (13.0 ± 2.0), sex and writing hand, observed sequences of static body postures that showed either fluent or non-fluent motion, in which only the fluent condition depicted apparent biological motion. Using a recently validated paradigm combining EEG frequency tagging and apparent biological motion (Cracco et al., 2023), the perception of biological motion was contrasted with the perception of individual body postures., Outcomes and Conclusions: Children with DCD did not show reduced sensitivity to apparent biological motion compared with typically developing children. However, the DCD group did show a reduced brain response to repetitive visual stimuli, suggesting altered predictive processing in the perceptual domain in this group. Suggestions for further research on biological motion perception in DCD are identified., Competing Interests: Declaration of Competing Interest The authors declared that they had no conflict of interest with respect to their authorship or the publication of this article., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: To better personalize treatment and monitor recovery of individuals with low back pain, objective tests of sensorimotor functions, such as lumbar proprioception, must be selected based on their reliability and validity. The primary objective of this study was to test the concurrent validity of three measures of lumbar proprioception., Methods: Thirty-one participants performed three lumbar proprioception tests (motion perception threshold, active and passive joint positioning sense), a whole-body mobility and balance (time up-and-go) and two trunk-specific postural control (threshold of stability and sensor-based sway measures) tests., Results: Only the motion perception threshold proprioception test showed some validity, correlating with the trunk-specific postural control tests [r range (positive values): 0.37 to 0.60]. The three lumbar proprioception measures were not correlated to each other. The threshold of stability measure was correlated with the time up-and-go (r = 0.37) and trunk-specific (sensor-based sway measures) postural control [r range (positive values): 0.48 to 0.77] tests., Conclusion: The present study generated three original findings. Only the motion perception threshold proprioception test demonstrated its concurrent validity. In fact, the three lumbar proprioception tests performed in the present study were not correlated to each other, thus assessing different constructs. Finally, the threshold of stability protocol was validated against other tests. These findings will help in selecting the most appropriate lumbar proprioception measures to study the effects of exercise treatments in patients with back pain., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Two vestibular signals, rotational and inertial cues, converge for the perception of complex motion. However, how vestibular perception is built on neuronal behaviors and decision-making processes, especially during the simultaneous presentation of rotational and inertial cues, has yet to be elucidated in humans. In this study, we analyzed the perceptual responses of 20 participants after pairwise rotational experiments, comprised of four control and four test sessions. In both control and test sessions, participants underwent clockwise and counterclockwise rotations in head-down and head-up positions. The difference between the control and test sessions was the head re-orientation relative to gravity after rotations, thereby providing only rotational cues in the control sessions and both rotational and inertial cues in the test sessions. The accuracy of perceptual responses was calculated by comparing the direction of rotational and inertial cues acquired from participants with that predicted by the velocity-storage model. The results showed that the accuracy of rotational perception ranged from 80 to 95% in the four control sessions but significantly decreased to 35 to 75% in the four test sessions. The accuracy of inertial perception in the test sessions ranged from 50 to 70%. The accuracy of rotational perception improved with repetitive exposure to the simultaneous presentation of both rotational and inertial cues, while the accuracy of inertial perception remained steady. The results suggested a significant interaction between rotational and inertial perception and implied that vestibular perception acquired in patients with vestibular disorders are potentially inaccurate., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Although previous studies have observed increased global network integration during tasks in persons with mild cognitive impairment (MCI), the association between this integration and actual task performance has remained unexplored. Understanding this link is crucial for uncovering the underlying mechanism behind these changes in network integration and their potential role in MCI. Here, to find such a link, we investigated brain network integration derived from electroencephalography recordings during a visual motion discrimination task in older adults with MCI and those with normal cognition. We focused on a critical period just before stimulus presentation, which is known to be important for task performance. Our results revealed that during this period, MCI patients exhibited increased network integration compared to controls. Interestingly, increased integration was associated with worse task performance in the MCI group, suggesting it was not beneficial. No such association was found in the control group. Notably, this difference existed despite similar overall task performance between the groups. This suboptimal integration pattern during the cognitive task might reflect network de-differentiation due to disinhibition in MCI patients. Collectively, our study highlights the potential of analysing network integration during tasks to identify cognitive impairment and suggest a distinct role for network integration in MCI patients compared with healthy controls., (© 2024 The Author(s). European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)

The informal heuristic practices of the fine arts have much to offer to our understanding of the appearance of phenomenological reality. One interesting example is the use of exaggeration to enhance the illusion of liveliness in both living and nonliving subjects. This further eases the uncomfortable sense that the motion is somehow uncanny - especially with inanimate objects. We performed a series of experiments to test the effects of exaggeration on the phenomenological perception of simple animated objects - bouncing balls. A physically plausible model of a bouncing ball was augmented with a frequently used form of exaggeration known as squash and stretch. Observers were shown a series of animated balls, depicted using systematic parameterizations of the exaggeration model, and asked to rate their plausibility. A range of rendering styles provided varying levels of information as to the type of ball. In all cases, balls with small amounts of exaggeration were seen as plausible as those without any exaggeration (e.g., with veridical motion). Furthermore, when the type of ball was not specified, observers tolerated a large amount of exaggeration before judging them as implausible. When the type of ball was indicated, observers narrowed the range of acceptable exaggeration somewhat but still tolerated exaggeration well beyond that which would be physically possible. We contend that, in this case, exaggeration acts to bridge the so-called uncanny valley for artificial depictions of physical reality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

A recent model of face processing proposes that face shape and motion are processed in parallel brain pathways. Although tested in neuroimaging, the assumptions of this theory remain relatively untested through controlled psychophysical studies until now. Recruiting undergraduate students over the age of 18, we test this hypothesis using a tight control of stimulus factors, through computerized three-dimensional face models and calibration of dimensional discriminability, and of decisional factors, through a model-based analysis using general recognition theory (GRT). Theoretical links between neural and perceptual forms of independence within GRT allowed us to derive the a priori hypotheses that perceptual separability of shape and motion should hold, while other forms of independence defined within GRT might fail. We found evidence to support both of those predictions., (© 2024. The Psychonomic Society, Inc.)