Search

Recent studies have shown that gait synchronization during natural walking is not merely anecdotal, but it is a repeatable phenomenon that is quantifiable and is apparently related to available sensory feedback modalities. However, the mechanisms underlying this phase-locking of gait have only recently begun to be investigated. For example, it is not known what role, if any, attention plays. We employed a dual tasking paradigm in order to investigate the role attention plays in gait synchronization. Sixteen pairs of subjects walked under six conditions that manipulated the available sensory feedback and the degree of difficulty of the dual task, i.e., the attention. Movement was quantified using a trunk-mounted tri-axial accelerometer. A gait synchronization index (GSI) was calculated in order to quantify the degree of synchronization of the gait pattern. A simple dual task resulted in an increased level of synchronization, whereas a more complex dual task lead to a reduction in synchronization. Handholding increased synchronization, compared to the same attention condition without handholding. These results indicate that in order for two walkers to synchronize, some level of attention is apparently required, such that a relatively complex dual task utilizes enough attentional resources to reduce the occurrence of synchronization.

A long-standing controversy in social attention debates whether gaze-of-another induces reflexive shifts of one's own attention. In attempting to resolve this controversy, we utilized a novel Stroop task, the PAT Stroop, in which pro- and anti-saccade (PAT) responses are made to competing gaze and peripheral stimuli. The first experiment demonstrated a "Stroop effect" for peripheral stimuli, i.e. peripheral distractors interfered with gaze triggers, but gaze distractors did not interfere with peripheral triggers. These results were replicated in the second experiment, which also negated the possibility that the mere display and practice of the "clean PAT" influenced the results. Thus, the use a new PAT Stroop task demonstrated reflexive supremacy of peripheral stimuli over gaze stimuli. This novel variant of the Stroop task demonstrated similar characteristics to the classic color naming Stroop - i.e. an asymmetrical pattern, and again showed the utility and versatility of stoop-like tasks in probing mental tasks.

Complex post-traumatic stress disorder (CPTSD) is a psychiatric diagnosis that includes three additional symptom clusters beyond those necessary for post-traumatic stress disorder (PTSD) diagnosis. CPTSD is typically associated with a prolonged trauma exposure in which a person's destiny is under the control of other people and escape is not an option. Insomnia prevalence in women suffering from CPTSD was compared to the prevalence of insomnia in those with no-PTSD and those with only PTSD. Yazidi women (N = 108, age = 24.41 ± 5.71) former captives of the Islamic State terrorist group were queried about captivity variables, psychological distress, resilience, PTSD, CPTSD, and insomnia. CPTSD prevalence was high (>50%) and was highly correlated with insomnia (95% of those with CPTSD had insomnia). A dichotomous insomnia variable was regressed on age and marital-status (Step 1), captivity-duration and number of fellow captives (Step 2), resilience and psychological distress (Step 3), and group (no-PTSD/PTSD/CPTSD) (Step 4). Insomnia was 18 times more likely in the CPTSD group than in the no-PTSD group. There were no differences in insomnia prevalence between the no-PTSD and PTSD groups. Insomnia levels among Yazidi women released from captivity support an understanding of CPTSD as a separate entity than PTSD. Potential factors linking CPTSD to insomnia, beyond those associated with PTSD are discussed.

OBJECTIVE: Adults diagnosed with attentional deficit disorder (ADHD) are easily distracted in many tasks. Yet ADHD performance on inattentional blindness (IB) tasks has not been examined. Such investigation may aid in discriminating between 3 ADHD models: the neurological model, the perceptual load theory, and the "hunter versus farmer" hypothesis. METHOD: Distractibility was assessed in ADHD and non-ADHD college students using the MOXO task that involves detection of a single attended stimulus that repeatedly appears in the same place and in the well-known IB "gorilla" video which involves tracking of a stimulus moving at a fast pace in a dynamic, complex manner. RESULTS: ADHD college students showed increased distractibility in the MOXO task. By contrast, they performed better than controls in the attended channel of the IB task, while they were also better at noticing the unattended stimuli and thus exhibiting little-to-no inattentional blindness. CONCLUSIONS: As no attentional tradeoffs were evident in the IB task, it appears that the results are most consistent with the "hunter versus farmer" hypothesis, which postulates that ADHD individuals have an alternative cognitive style which is less equipped to deal with detection of repeated stimuli while comprising advantages in the tracking of stimuli moving in a fast dynamic manner. (PsycINFO Database Record (c) 2015 APA, all rights reserved). Language: en

Vestibulo-Ocular Reflex (VOR) abnormalities in cerebellar ataxias are a matter of renewed interest. We have previously reported vestibular areflexia in a group of Yemenite-Jews with Spinocerebellar Ataxia Type 3 (SCA3) who had clear bilateral pathological horizontal Head Impulse Test (HIT). The objective of this study was to evaluate the VOR of ten SCA3 patients who have variable bedside HIT responses by recording their eye movements using magnetic search coils and to correlate these results with their clinical and genetic data. Eight out of the ten patients have abnormal horizontal HIT detected by both clinical bedside examination and laboratory tests. Results of bedside HIT testing were significantly correlated with the VOR gain recorded using magnetic search coils. No significant correlations were found between VOR gain and other clinical or genetic data. Our study confirms the presence of defective VOR in SCA3 patients and corroborates the useful of the HIT as a reliable bedside test for diagnosis of VOR deficits.

The injustices and atrocities of Nazi medicine were of catastrophic proportions. It is now well known that Nazi physicians during the Nazi era not only participated willingly in many of the inhuman...

Human beings have engaged in animal husbandry and have slaughtered animals for food for thousands of years. During the majority of that time most societies had no animal welfare regulations that governed the care or slaughter of animals. Judaism is a notable exception in that from its earliest days it has included such rules. Among the Jewish dietary laws is a prohibition to consume meat from an animal that dies in any manner other than through the rigorously defined method of slaughter known as shechita. In recent decades more and more attempts have been initiated by governments around the world to either outright ban or to control and modify the practice of shechita. This paper presents the requisite background about shechita and then analyzes the ethics of some of the recent legislation. The analysis includes a rebuttal of the assertion that shechita is an inhumane method of slaughter. It further presents the consequences on the Jewish community of legislation to impose pre-slaughter stunning and explains why such legislation is unethical. The actual effect of labeling laws is discussed and it is shown why such laws are also un-ethical.

Aim The aim of this study was to evaluate an interdisciplinary visual assessment for multiply challenged children diagnosed with cerebral palsy (CP). Method A comprehensive ophthalmological assessment together with a visual classification scale (VCS) and a questionnaire evaluating daily visual function were completed regarding 77 children (41 females, 36 males; age range 3–20y; mean age 8y 3mo [SD 4y 3mo]; Gross Motor Function Classification System [GMFCS] level V; Manual Ability Classification System level V) who were diagnosed with CP (79.2% spastic quadriplegia, 6.5% athetoid quadriplegia, 10.4% mixed type, 3.9% hemiplegia). All participants had severe to profound motor and intellectual disability and an inability to communicate consistently through either verbal or assisted communication. The interrater and test–retest reliability of the questionnaire and its validity in comparison with the VCS were examined. In addition, the contribution of ophthalmological testing in predicting daily visual function was assessed. Results The ophthalmological examination revealed three diagnostic subgroups: a group with cerebral visual impairment (CVI), a group with optic atrophy, and a group without visual impairment. The questionnaire was found to have high values of interrater reliability (interclass correlation coefficient [ICC]=0.873; 95% confidence interval [CI] 0.762–0.935) and test–retest reliability (ICC=0.988; 95% CI 0.964–0.996). Validity was established for the questionnaire factors: task-orientated visual function (r=0.802; 95% CI 0.669–0.885) and basic visual skills (r=0.691; 95% CI 0.504–0.816). The questionnaire provided information about daily visual performance not available from one-time ophthalmological testing, particularly for participants diagnosed with CVI. The visual performance scale significantly predicted daily visual function for all groups. Interpretation This study highlights the benefits of implementing a diagnostic performance scale as well as a reliable functional questionnaire to achieve a precise visual assessment of children with severe neurological impairment.

Perceptual bias in simple visuospatial tasks, such as line bisection seen among healthy dextrals, has often been attributed to the hemispheric activation hypothesis. The often reported leftward perceptual bias was explained by an activation of the right hemisphere during visuospatial tasks. However, imposed scanning direction and stimuli saliency have also been used to explain these spatial asymmetries. One example of scanning direction is the well-trained one resulting from reading direction. Here, we present studies that target the role of reading direction on nonverbal tasks: line bisection, esthetic preference, and straight-ahead pointing by comparing left-to-right and right-to-left readers. The findings are discussed regarding the interaction between cultural factors, such as reading habits, and biological factors, such as cerebral lateralization.

Ethical considerations of transnational gestational surrogacy, and in particular the potentially exploitative aspect of recruiting foreign candidates, are addressed in Kirby's insightful article (2...

Capitalism has been shown to be the most successful economic system, one that creates more prosperity than any other and benefits the consumer in many ways. A mainstay of capitalism is the free mar...

Samuel Golubchuk was unwittingly at the center of a medical controversy with important ethical ramifications. Mr. Golubchuk, an 84-year-old patient whose precise neurological level of function was open to debate, was being artificially ventilated and fed by a gastrostomy tube prior to his death. According to all reports he was neither brain dead nor in a vegetative state. The physicians directly responsible for his care had requested that they be allowed to remove the patient from life support against the wishes of the patient's family. Concurrently the Manitoba College of Physicians and Surgeons released a statement which states that the final decision to withdraw life support lies with the physician. In our opinion the statement is ethically problematic for a number of reasons. 1. It is an affront to the guiding principles of Western medical ethics: patient autonomy and human freedom. 2. The position of Samuel Golubchuk's physicians and the new statement lack cultural sensitivity towards other traditions. 3. In modern society there exists an erosion of a basic attitude towards the value of life. 4. The ability of physicians to predict life expectancy in terminally ill patients has been shown repeatedly to be quite limited.

Previous research has suggested that the physical aspects of human nature in general, and physical human frailties in particular become disagreeable and repugnant following death primes. The current research tested this hypothesis in two studies using an eye-tracking methodology. Participants were subliminally primed with death or with a control word and then viewed a series of arrays containing four pictures each, during which their eye-movements were monitored. In Study 1, the arrays included pictures of physical injury or neutral objects, and in Study 2 pictures of physical injury, threatening images, and neutral objects. The results indicated that in both studies death primes significantly decreased gaze duration towards pictures of physical injury, and did not have a significant effect on gaze duration towards neutral images. However, in Study 2 death primes increased gaze duration towards threatening images. The discussion examines the role of motivated unconscious attention in terror management processes.

Palliation of pain is universally regarded as a cardinal aspect of end-of-life care. In the early days of the palliative care and hospice movement there was concern that aggressive pain control with opioids could potentially hasten the death of the patient primarily through respiratory depression. For many ethicists and theologians who were opposed to active euthanasia, this raised the difficult question of whether it is permissible to use these potentially harmful medications. Traditional Jewish decisors also addressed this question and their writings can shed light on their attitudes toward terminal care. The purpose of this article is to analyze the view of three highly respected authorities on the use of pain medications with potentially significant side effects in terminal patients. The Jewish position demonstrates how an ancient tradition struggles to develop an ethic consistent with modern sensibilities. Religious decisors scour the ancient sources to find precedents and then apply that wisdom to contemporary questions. Jewish medical ethics by its very nature is highly pluralistic because there is no central body that determines policy and a wide spectrum of opinions are usually found. However, regarding pain treatment there appears to be a broad consensus mandating its aggressive use even at the risk of significant side effects as long as the motivation is relief of suffering.

International audience; The present study aimed to show that bidirectional reading and language exposure influence the position of egocentric reference (ER), the perceived direction of the body's sagittal axis proposed to act as an anchor for movements in extracorporeal space. Directional factors (e.g., visual scanning bias and reading habits) have been proposed to influence visuospatial performance, such as in line bisection and figure drawing. In past studies, bidirectional readers have been less consistent in demonstrating a bias compared to unidirectional readers. Using a straight-ahead pointing task to assess egocentric reference, we compared 14 unidirectional left-to-right readers (Uni-LR) to three bidirectional reading groups that differed in the reading direction of their native language and/or the level of their second language literacy: 16 low-English literate, native right-to-left, bidirectional readers (Lo-Bi-RL), 13 high-English literate, native right-to-left, bidirectional readers (Hi-Bi-RL), and 15 native left-to-right, bidirectional readers (Bi-LR). Participants were asked to point straight-ahead while blindfolded using either a left-to-right or a right-to-left scanning direction to approach the subjective sagittal midline. Uni-LRs showed left-side spatial bias when scanning left-to-right and right-side bias during right-to-left scanning, Bi-LRs and Lo-Bi-RLs (i.e., intermediate level or less in their second language) demonstrated the opposite pattern, and Hi-Bi-RLs showed left-side spatial bias regardless of scanning direction. Results are discussed in terms of accuracy and spatial bias regarding the interaction between reading direction and spatial cognition based on the level of bidirectional literacy and language exposure.

The present study investigates the performance of persons with reading disabilities (PRD) on a variety of sequential visual-comparison tasks that have different working-memory requirements. In addition, mediating relationships between the sequential comparison process and attention and memory skills were looked for. Our findings suggest that PRD perform worse than normally achieving readers (NAR) when the task requires more than a minimal amount of working memory, unrelated to presentation rate. We also demonstrate high correlations between performance on the task with the most working-memory demands and reading-related skills, suggesting that poor working-memory abilities may be one of the underlying mechanisms of dyslexia. The mediating model analysis indicates that order judgment tasks are mediating to verbal working memory, suggesting that visual sequence memory precedes auditory sequence memory. We further suggest that visual tasks involving sequential comparisons could probe for poor working memory in PRD.

Humans have a special ability to recognize human faces that transcends and is separate from the usual discrimination abilities of the visual system. Schizophrenia patients are known to have an impaired ability to recognize facial affect, a deficit that may stem from a more profound problem of face identification and perception. The special skill of detecting human faces relies upon numerous capabilities, including gestalt perception, "filling-in", and proper gaze scanning, facilities that recent research has shown to be deficient in schizophrenia patients. We therefore hypothesized that schizophrenia patients have a deficit in their perception and structural analysis of human faces that will manifest in their difficulty in detecting faces hidden within neutral pictures. We tested the ability of 35 schizophrenia patients and 32 healthy controls at detecting hidden human faces and animals or animal faces hidden within eight pictures. Overall, the patients recognized fewer items compared to controls, however, it was specifically the human faces in which this difference was significant, suggesting that schizophrenic patients have a specific deficit in their human face recognition system.

When we fixate our gaze on a stable object, our eyes move continuously with extremely small involuntary and autonomic movements, that even we are unaware of during their occurrence. One of the roles of these fixational eye movements is to prevent the adaptation of the visual system to continuous illumination and inhibit fading of the image. These random, small movements are restricted at long time scales so as to keep the target at the centre of the field of view. In addition, the synchronisation properties between both eyes are related to binocular coordination in order to provide stereopsis. We investigated the roles of different time scale behaviours, especially how they are expressed in the different spatial directions (vertical versus horizontal). We also tested the synchronisation between both eyes. Results show different scaling behaviour between horizontal and vertical movements. When the small ballistic movements, i.e., microsaccades, are removed, the scaling behaviour in both axes becomes similar. Our findings suggest that microsaccades enhance the persistence at short time scales mostly in the horizontal component and much less in the vertical component. We also applied the phase synchronisation decay method to study the synchronisation between six combinations of binocular fixational eye movement components. We found that the vertical-vertical components of right and left eyes are significantly more synchronised than the horizontal-horizontal components. These differences may be due to the need for continuously moving the eyes in the horizontal plane in order to match the stereoscopic image for different viewing distances.

Individuals with schizophrenia are known to demonstrate reduced or reversed brain asymmetry. While much is known regarding anatomical brain asymmetry, little is known about how this affects the individual at the functional level. Based on the known leftward bias in normal individuals, the aim of this study was to explore whether any difference in this function would be noted in schizophrenia. This study therefore investigated the phenomenon of functional asymmetry in schizophrenia patients by means of the following tasks: line bisection, line trisection (assessing hemifield spatial neglect) and letter cancellation (assessing contralateral visuospatial exploration). Forty-five schizophrenia inpatients maintained on antipsychotic medication were evaluated. Transections were measured for accuracy, lateralization, and directional bias. In the line bisection task subjects indicated no pseudo-neglect, thus differing from a normal, leftward bias. In the line trisection there was a significant preference to perform the ambiguous instruction on the right side, with no consistent bias in accuracy. Irrespective of conditions, in the letter cancellation task there was always a significant tendency to succeed on the left third compared to the right third. Results may support findings in schizophrenia indicating decreased or altered function of the left hemisphere.

Terror exposure has become commonplace in Israel, with civilians needing to develop appropriate coping mechanisms. This study investigated coping mechanisms of those who are able to return to leisure activity at sites of previous terror attacks. A specially designed questionnaire, exploring knowledge of the terror event, previous terror exposure, coping mechanisms, state of anxiety, and mood, was administered to 93 restaurant attendees at sites of well-known recent terror attacks (2001-2005). Most respondents were aware of the previous terror attack (92.3%) and most reported no fear at revisiting (70.3%), with 20.9% reporting some anxiety and 5.5% reporting moderate or severe anxiety. Sixty percent reported that they have no fear that a terror attack will reoccur at the same place. Some (27.7%) reported change in practices or decrease in one or more activity, especially use of public transport (18%). The most helpful reported resource for facilitating stress coping following a suicide bombing was to "call or be in touch with friends or relatives," and least helpful was "medicines." Over half of respondents (53%) reported that the current security climate affected their mood. Older individuals and females were more affected by terror events. Study observations confirm that resilience develops in the general population in response to ongoing terror attacks. Response to terror is heterogeneous with a range of coping mechanisms expressed.

Presenting a subject with two random-dot flow fields produces a persuasive 3D percept of a rotating cylinder whose perceived direction of rotation is bi-stable and reverses spontaneously. When real reversals are introduced subjects rarely perceive them. It is possible that although these reversals are consciously ignored, they are registered and available to the visual system for potential later use. We tested this prediction by comparing the number of spontaneously perceived reversals with and without real reversals. We found that although the actual reversals were usually not perceived, they nonetheless increased the number of spontaneous flips. The visual system apparently prefers to retain global structure rather than perceive a motion change of every element in the stimulus. However, it does not completely ignore the changes and incorporates them into other emerging interpretations. These findings argue against the fatigue hypothesis of spontaneous reversals which would predict a decrease in the number of reversals and can be interpreted as supporting the information-processing view by noting that due to the real reversals, the visual system continues to accrue data that argues against the current representation and facilitates switching to the rival representation.

Purpose A primary task of the eye care professional is determining the refraction, or optical correction, of a patient. The duochrome red-green test is a standard tool for verification of the final refraction. Traditionally, it is recommended for use both prior to and subsequent to determining the cylindrical or astigmatic component of the refraction. In order for it to be effective when used before correcting the cylinder it is necessary that the COLC (Circle of Least Confusion) be on the retina. This study examined whether it is necessarily true that the duochrome response in uncorrected astigmatism will be as trust-worthy as it is with corrected cylinders. Methods The red-green examination was performed monocularly under the following three conditions: a. fully corrected refraction for the subgroup of eyes that had spherical refractions and for the subgroup of eyes with sphero-cylindrical refractions. b. best sphere-only correction without cylinder correction in sphero-cylindrical eyes c. an induced cylinder error in spherical eyes. The interval between the last “red” response and the first “green” response for the right eyes as a group and separately for the physiological cylinder and induced cylinder correction sub-groups was calculated and compared using a paired, two-tailed t-test. Results The intervals between “red” and “green” responses were not significantly different in the population as a whole and in the uncorrected physiological cylinder and induced cylinder subgroups examined. Conclusion Based on the finding that the interval of red-green equality with fully corrected cylinder and without the cylindrical correction are not significantly different, the red-green duochrome test can indeed be used both before and after cylindrical correction.

Food deprivation has been shown to deleteriously affect human cognition, but findings are equivocal, and few studies have examined several cognitive domains. In this study, the authors used computerized testing to describe the profile of shifts in cognition attributable to short-term religious fasting. Multiple cognitive domains were evaluated at midday and late afternoon following complete abstention from eating and drinking beginning at midnight. Cross-domain, fasting-related deficits were found for tasks requiring perception of spatial relations. Fasting-related information processing deficits were found for response time but not accuracy for test levels of intermediate difficulty. Time-of-day effects often reflected poorer afternoon performance. These findings provide a detailed profile of cognitive consequences of food deprivation, affected by time of day, task demands, and type of outcome.

Stiff-Person Syndrome (SPS) is an immune-mediated disorder of the central nervous system characterized by muscle rigidity, episodic muscle spasms, and high titers of antibodies against glutamic acid decarboxylase (GAD). The presence of cerebellar ataxia in SPS is extremely rare, but occurs. Clinical observations of ocular motor abnormalities have been noted in a few SPS patients. The purpose of this study is to provide a detailed quantitative documentation of ocular motor abnormalities in a patient with SPS and progressive cerebellar signs. Detailed clinical assessment of a woman with SPS and precise eye movement recordings using the magnetic search coil technique was performed. In addition to other ocular motor abnormalities that included longer latencies for saccades, downbeat nystagmus, and loss of downward smooth pursuit, a rare saccade velocity profile consisting of multi-component saccades was observed. We postulate that these ocular motor findings are related to impairment of GABAergic neurotransmission because antibodies to glutamic acid decarboxylase (GAD-Abs) have been implicated in the pathogenesis of both SPS and some cases of cerebellar ataxia. In addition, this unusual saccadic velocity profile may have important implications for modeling the saccadic system and furthering a complete understanding of saccade generation.

The visual system uses the pattern of motion on the retina to analyze the motion of objects in the world, and the motion of the observer him/herself. Distinguishing between retinal motion evoked by movement of the retina in space and retinal motion evoked by movement of objects in the environment is computationally difficult, and the human visual system frequently misinterprets the meaning of retinal motion. In this study, we demonstrate that the visual system of the Rhesus monkey also misinterprets retinal motion. We show that monkeys erroneously report the trajectories of pursuit targets or their own pursuit eye movements during an epoch of smooth pursuit across an orthogonally moving background. Furthermore, when they make saccades to the spatial location of stimuli that flashed early in an epoch of smooth pursuit or fixation, they make large errors that appear to take into account the erroneous smooth eye movement that they report in the first experiment, and not the eye movement that they actually make.

This study examined the relationship between gender and strategies for coping for individuals faced with a perceived major, life-threatening stressor. The focus here was the sniper(s) that terrorized the greater Washington, D.C. metropolitan area for over 3 weeks in October 2002. A retrospective survey of 144 random respondents regarding their behavior and coping mechanisms during this period indicated that, overall, women's behavior was affected more than men's. Unexpectedly, most emotion-focused coping mechanisms studied here yielded no significant gender differences. The findings are discussed in light of recent thinking in social psychology on sex-role stereotyping and risk-taking. Copyright © 2004 John Wiley & Sons, Ltd.

Gaze-evoked blinks are contractions of the orbicularis oculi (OO)—the lid closing muscle—occurring during rapid movements of the head and eyes and result from a common drive to the gaze and blink motor systems. However, blinks occurring during shifts of gaze are often suppressed when the gaze shift is made to an important visual stimulus, suggesting that the visual system can modulate the occurrence of these blinks. In head-stabilized, human subjects, we tested the hypothesis that the presence of a visual stimulus was sufficient, but not necessary, to modulate OO EMG (OOemg) activity during saccadic eye movements. Rapid, reorienting movements of the eyes (saccades) were made to visual targets that remained illuminated (visually guided trials) or were briefly flashed (memory-guided trials) at different amplitudes along the horizontal meridian. We measured OOemg activity and found that the magnitude and probability of OOemg activity occurrence was reduced when a saccade was made to the memory of the spatial location as well as to the actual visual stimulus. The reduced OOemg activity occurred only when the location of the target was previously cued. OOemg activity occurred reliably with spontaneous saccades that were made to locations with no explicit visual stimulus, generally, back to the fixation location. Thus the modulation of gaze-evoked OOemg activity does not depend on the presence of visual information per se, but rather, results from an extraretinal signal.

The pro and anti-saccade task (PAT) is a widely used tool in the study of overt and covert attention with promising potential role in neurocognitive and psychiatric assessment. However, specific PAT protocols can vary significantly between labs, potentially resulting in large variations in findings across studies. In light of recent calls towards a standardization of PAT the current study's objective was to systematically and purposely evaluate the effects of block vs. interleaved administration—a fundamental consideration—on PAT measures in a within subject design. Additionally, this study evaluated whether measures of a Posner-type cueing paradigm parallels measures of the PAT paradigm. As hypothesized, results indicate that PAT performance is highly susceptible to administration mode. Interleaved mode resulted in larger error rates not only for anti (blocks: M = 22%; interleaved: M = 42%) but also for pro-saccades (blocks: M = 5%; interleaved: M = 12%). This difference between block and interleaved administration was significantly larger in anti-saccades compared to pro-saccades and cannot be attributed to a 'speed/accuracy tradeoff'. Interleaved mode produced larger pro and anti-saccade differences in error rates while block administration produced larger latency differences. Results question the reflexive nature of pro-saccades, suggesting they are not purely reflexive. These results were further discussed and compared to previous studies that included within subject data of blocks and interleaved trials.

Sonya Charles (2011) accuses the American College of Obstetrics and Gynecology (ACOG) of using practices that mirror those of abusive men. Among her criticisms is the charge that ACOG acts paternal...

There are presently several ongoing clinical trials to provide usable sight to profoundly visually impaired patients by means of electrical stimulation of the retina. Some of the blind patients implanted with retinal prosthesis reported un-patterned perception and yet benefit from the device in many activities of daily living, seemingly because they adopt active scanning strategies. The aim of the present work is to evaluate if and under what conditions a measured visual acuity level is truly an indication that the brain perceived a patterned image from the electrical stimulation of the visual prosthesis. Sighted subjects used a pixelized simulator in which they perceived either a low resolution sub-sampling of the original image (“normal mode” – patterned vision) or an image that was solely a function of the brightness and size of the original image (“brightness mode” – no patterned vision). Results show that subjects were able to adopt a head scanning strategy that enabled acuity beyond the resolution set by a static view of the stimulus. In brightness mode, i.e. without patterned vision, most subjects achieved a measurable acuity level better than the limit set by the geometrical resolution of the entire array but worse than the limit set by the distance between neighboring simulated pixels. In normal mode all subject achieved acuity level that is better than the geometrical resolution of the simulated pixels. Thus, visual acuity levels comparable with the electrodes/pixels resolution implies that the patient perceives an image with spatial patterns.

HIV-positive individuals have traditionally been barred from donating organs due to transmission concerns, but this barrier may soon be lifted in the USA in limited settings when recipients are also infected with HIV. Recipients of livers and kidneys with well-controlled HIV infection have been shown to have similar outcomes to those without HIV, erasing ethical concerns about poorly chosen beneficiaries of precious organs. But the question of whether HIV-negative patients should be disallowed from receiving an organ from an HIV-positive donor has not been adequately explored. In this essay, we will discuss the background to this scenario and the ethical implications of its adoption from the perspectives of autonomy, beneficence/non-maleficence and justice.

Ballantyne and colleagues (2009) cogently present the conflict that arises in jurisdictions in which prenatal diagnosis (PND) is available and abortions are prohibited. They primarily focus on two ...

Jeremy Snyder (2009) objects to the use of the term “poaching” in describing the migration of healthcare workers from poor to richer countries, and in so doing minimizes the culpability of destinat...

Eye movements were recorded from three subjects as they initiated tracking of a small circle (“target”) moving leftward or rightward, above or below the horizontal meridian, either alone or in the presence of a small square (“distractor”) moving leftward or rightward on the other side of the horizontal meridian. At the start of each trial, subjects were provided with either a “form” cue (always centrally positioned and having the circular shape and color of the upcoming moving target) or a “location” cue (a small white square positioned where the upcoming target would appear). The latency of pursuit increased in the presence of an oppositely moving distractor when subjects were provided the form cues but not when they were provided the location cues. The latency of saccades showed similar, but smaller, increases when subjects were given the form cues. On many trials with the form cues, pursuit started in the direction of the distractor and then reversed to follow the target. On these trials, the initial saccade often, but not always, also followed the distractor. These results indicate that the mechanisms of target selection for pursuit and saccades are tightly coordinated but not strictly yoked. The shared effects of the distractor on the latencies of pursuit and saccades probably reflect the common role of visual attention in filtering the inputs that guide these two types of eye movements. The differences in the details of the effects on pursuit and saccades suggest that the neural mechanisms that trigger these two movements can be independently regulated.

A dominant feature of anorexia nervosa (AN) is an aversion to food that is driven by an unhealthy fear of gaining weight and by a distorted self-image in which sufferers perceive themselves as heav...

We compared the accuracy of oblique, memory-guided saccades if the eye is stationary or moves horizontally during the memory period. We studied 11 patients with cerebellar disease and 11 age-matched control subjects. Normal subjects showed similar accuracy of saccades for both conditions. In contrast, all patients showed greater errors if the eye moved horizontally during the memory period; however, errors of both vertical and horizontal components of memory-guided saccades were similar. Thus, inaccuracy of memory-guided saccades could not be simply attributed to failure to internally monitor change in horizontal gaze during the memory period. Instead, we propose that the greater saccadic errors which occurred when gaze changed during the memory period reflected a disruption of predictive mechanisms governing eye movements.

Rottach, Klaus G., Vallabh E. Das, Walter Wohlgemuth, Ari Z. Zivotofsky, and R. John Leigh. Properties of horizontal saccades accompanied by blinks. J. Neurophysiol. 79: 2895–2902, 1998. Using the magnetic search coil technique to record eye and lid movements, we investigated the effect of voluntary blinks on horizontal saccades in five normal human subjects. The main goal of the study was to determine whether changes in the dynamics of saccades with blinks could be accounted for by a superposition of the eye movements induced by blinks as subjects fixated a stationary target and saccadic movements made without a blink. First, subjects made voluntary blinks as they fixed on stationary targets located straight ahead or 20° to the right or left. They then made saccades between two continuously visible targets 20 or 40° apart, while either attempting not to blink, or voluntarily blinking, with each saccade. During fixation of a target located straight ahead, blinks induced brief downward and nasalward deflections of eye position. When subjects looked at targets located at right or left 20°, similar initial movements were made by four of the subjects, but the amplitude of the adducted eye was reduced by 65% and was followed by a larger temporalward movement. Blinks caused substantial changes in the dynamic properties of saccades. For 20° saccades made with blinks, peak velocity and peak acceleration were decreased by ∼20% in all subjects compared with saccades made without blinks. Blinks caused the duration of 20° saccades to increase, on average, by 36%. On the other hand, blinks had only small effects on the gain of saccades. Blinks had little influence on the relative velocities of centrifugal versus centripetal saccades, and abducting versus adducting saccades. Three of five subjects showed a significantly increased incidence of dynamic overshoot in saccades accompanied by blinks, especially for 20° movements. Taken with other evidence, this finding suggests that saccadic omnipause neurons are inhibited by blinks, which have longer duration than the saccades that company them. In conclusion, the changes in dynamic properties of saccades brought about by blinks cannot be accounted for simply by a summation of gaze perturbations produced by blinks during fixation and saccadic eye movements made without blinks. Our findings, especially the appearance of dynamic overshoots, suggest that blinks affect the central programming of saccades. These effects of blinks need to be taken into account during studies of the dynamic properties of saccades.

The Talmud, a massive Jewish work completed in Persia approximately 1500 years ago, contains references to a fish named the shibuta. Various previous attempts to identify it over the last several centuries took place in lands other than Iraq and consequently the true identity seems to have escaped those Jewish scholars. In this paper we summarize the previous work and present evidence to support the identification of the talmudic shibuta with Barbus grypus.

We measured the eye movements of three sisters with Niemann-Pick type C disease who had a selective defect of vertical saccades, which were slow and hypometric. Horizontal saccades, and horizontal and vertical pursuit and vestibular eye movements were similar to control subjects. The initial movement of oblique saccades was mainly horizontal and most of the vertical component occurred after the horizontal component ended; this resulted in strongly curved trajectories. After completion of the horizontal component of an oblique saccade, the eyes oscillated horizontally at 10–20 Hz until the vertical component ended. These findings are best explained by models that incorporate separate feedback loops for horizontal and vertical burst neurons, and in which the disease selectively affects vertical burst neurons.

We measured torsional eye movements induced by sinusoidal rotation or static tilt, of the head in roll while viewing a far or near target in 4 patients with skew deviation due to brainstem lesions, 4 patients with spasmodic torticollis (ST), 2 patients with unilateral eighth nerve section (VIIIS), and 10 normal subjects. Torsional nystagmus was present in all 4 patients with skew deviation. In subjects and patients, responses to both sinusoidal and static roll were larger while viewing the far target, consistent with factors dictated by geometry. Response gains to sinusoidal roll were abnormal in 3 patients with skew (increased in one, decreased in two), abnormal in 3 with ST (increased in 1, decreased in 2), and in abnormal both VIIIS patients (decreased). Greater abnormalities were evident in 3 skew patients while rolling away from the side of their brainstem lesions and in both VIIIS patients while rolling toward their lesioned ears. There were similar but less pronounced changes during static head roll. We conclude that patients with skew, ST, and VIIIS may all have abnormal ocular counter-rolling that is more evident during dynamic testing while viewing a far target. Such abnormalities endure because of the limited influence exerted by vision on torsional eye movements.

Abstract There is a very small, yet important minority within the community of European Union kosher consumers. There is a great deal of research regarding objective aspects of the kosher religious as well as civil laws and their implementation, but comparatively little research about the subjective attitudes, opinions, and concerns of those who actually purchase and consume kosher food. Such information can be important for a variety of interested parties including suppliers, distributors, regulatory agencies, legislators, and certifying agencies as well as religious authorities. We collected relevant data by organizing hour-long Focus Groups (FG) in five European cities and a suburb of Tel Aviv. The FG addressed consumer attitudes related to shopping practices, commitment, trust, and certification as well as their knowledge and opinions regarding nonhuman animal welfare as it relates to shechita (kosher slaughter) and knowledge of the issue of stunning animals at the time of killing. One of the significant findings was a high level of secularization among Jews that translates to a low level of commitment to eating kosher. But this was accompanied by assertions that eating kosher was an important religious obligation and complaints of low availability and high cost. There was a strong feeling, even among those less committed to eating kosher, that shechita was the preferred method of slaughtering an animal (more animal friendly) and a strong suspicion of anti-Semitism as a motivation for any attempt to impose a stunning obligation.

1. Measurements were made in four normal human subjects of the accuracy of saccades to remembered locations of targets that were flashed on a 20 x 30 deg random dot display that was either stationary or moving horizontally and sinusoidally at +/-9 deg at 0.3 Hz. During the interval between the target flash and the memory-guided saccade, the “memory period” (1.4 s), subjects either fixated a stationary spot or pursued a spot moving vertically sinusoidally at +/-9 deg at 0.3 Hz. 2. When saccades were made toward the location of targets previously flashed on a stationary background as subjects fixated the stationary spot, median saccadic error was 0.93 deg horizontally and 1.1 deg vertically. These errors were greater than for saccades to visible targets, which had median values of 0.59 deg horizontally and 0.60 deg vertically. 3. When targets were flashed as subjects smoothly pursued a spot that moved vertically across the stationary background, median saccadic error was 1.1 deg horizontally and 1.2 deg vertically, thus being of similar accuracy to when targets were flashed during fixation. In addition, the vertical component of the memory-guided saccade was much more closely correlated with the “spatial error” than with the “retinal error” this indicated that, when programming the saccade, the brain had taken into account eye movements that occurred during the memory period. 4. When saccades were made to targets flashed during attempted fixation of a stationary spot on a horizontally moving background, a condition that produces a weak Duncker-type illusion of horizontal movement of the primary target, median saccadic error increased horizontally to 3.2 deg but was 1.1 deg vertically. 5. When targets were flashed as subjects smoothly pursued a spot that moved vertically on the horizontally moving background, a condition that induces a strong illusion of diagonal target motion, median saccadic error was 4.0 deg horizontally and 1.5 deg vertically; thus the horizontal error was greater than under any other experimental condition. 6. In most trials, the initial saccade to the remembered target was followed by additional saccades while the subject was still in darkness. These secondary saccades, which were executed in the absence of visual feedback, brought the eye closer to the target location. During paradigms involving horizontal background movement, these corrections were more prominent horizontally than vertically. 7. Further measurements were made in two subjects to determine whether inaccuracy of memory-guided saccades, in the horizontal plane, was due to mislocalization at the time that the target flashed, misrepresentation of the trajectory of the pursuit eye movement during the memory period, or both. 8. The magnitude of the saccadic error, both with and without corrections made in darkness, was mislocalized by approximately 30% of the displacement of the background at the time that the target flashed. The magnitude of the saccadic error also was influenced by net movement of the background during the memory period, corresponding to approximately 25% of net background movement for the initial saccade and approximately 13% for the final eye position achieved in darkness. 9. We formulated simple linear models to test specific hypotheses about which combinations of signals best describe the observed saccadic amplitudes. We tested the possibilities that the brain made an accurate memory of target location and a reliable representation of the eye movement during the memory period, or that one or both of these was corrupted by the illusory visual stimulus. Our data were best accounted for by a model in which both the working memory of target location and the internal representation of the horizontal eye movements were corrupted by the illusory visual stimulus. We conclude that extraretinal signals played only a minor role, in comparison with visual estimates of the direction of gaze, in planning eye movements to remembered targ

Video-based eye-tracking systems are especially suited to studying eye movements during naturally occurring activities such as locomotion, but eye velocity records suffer from broad band noise that is not amenable to conventional filtering methods. We evaluated the effectiveness of combined median and moving-average filters by comparing prefiltered and postfiltered records made synchronously with a video eye-tracker and the magnetic search coil technique, which is relatively noise free. Root-mean-square noise was reduced by half, without distorting the eye velocity signal. To illustrate the practical use of this technique, we studied normal subjects and patients with deficient labyrinthine function and compared their ability to hold gaze on a visual target that moved with their heads (cancellation of the vestibulo-ocular reflex). Patients and normal subjects performed similarly during active head rotation but, during locomotion, patients held their eyes more steadily on the visual target than did subjects.

The Tullio phenomenon consists of vestibular symptoms on exposure to high-intensity acoustic stimuli, reflecting pathological stimulation of semicircular canals or otoliths. We report a patient with posttraumatic Tullio phenomenon to illustrate how precise measurement of eye movements during auditory stimulation, using the magnetic search coil technique, may characterize movements that are not clinically apparent or easily measured by other means. Such measurements in patients with surgically verified lesions may further elucidate the mechanisms responsible for this phenomenon.