Science.gov

Sample records for hand eye coordination

  1. Hand-Eye Coordinations.

    ERIC Educational Resources Information Center

    Getman, G. N.

    1985-01-01

    The article describes ways in which visual-tactual integration develops in young children and explains reasons for some children's failure. Procedures for teaching basic writing skills such as hand position, grouping of letters, and finally the writing of words are discussed. (CL)

  2. Hand-Eye Coordinations.

    ERIC Educational Resources Information Center

    Getman, G. N.

    1985-01-01

    The article describes ways in which visual-tactual integration develops in young children and explains reasons for some children's failure. Procedures for teaching basic writing skills such as hand position, grouping of letters, and finally the writing of words are discussed. (CL)

  3. Orientation in Eye-Hand Coordination Tasks.

    ERIC Educational Resources Information Center

    Eckert, Helen M.; Eichorn, Dorothy H.

    1978-01-01

    Longitudinal data on six eye-hand coordination tasks for 25 children aged five and one-half through eight and one-half years were factor analyzed in terms of functional and structural cognitive orientation. (Author)

  4. Orientation in Eye-Hand Coordination Tasks.

    ERIC Educational Resources Information Center

    Eckert, Helen M.; Eichorn, Dorothy H.

    1978-01-01

    Longitudinal data on six eye-hand coordination tasks for 25 children aged five and one-half through eight and one-half years were factor analyzed in terms of functional and structural cognitive orientation. (Author)

  5. Visuomotor transformations for eye-hand coordination.

    PubMed

    Henriques, D Y P; Medendorp, W P; Khan, A Z; Crawford, J D

    2002-01-01

    In recent years the scientific community has come to appreciate that the early cortical representations for visually guided arm movements are probably coded in a visual frame, i.e. relative to retinal landmarks. While this scheme accounts for many behavioral and neurophysiological observations, it also poses certain problems for manual control. For example, how are these oculocentric representations updated across eye movements, and how are they then transformed into useful commands for accurate movements of the arm relative to the body? Also, since we have two eyes, which is used as the reference point in eye-hand alignment tasks like pointing? We show that patterns of errors in human pointing suggest that early oculocentric representations for arm movement are remapped relative to the gaze direction during each saccade. To then transform these oculocentric representations into useful commands for accurate movements of the arm relative to the body, the brain correctly incorporates the three-dimensional, rotary geometry of the eyes when interpreting retinal images. We also explore the possibility that the eye-hand coordination system uses a strategy like ocular dominance, but switches alignment between the left and right eye in order to maximize eye-hand coordination in the best field of view. Finally, we describe the influence of eye position on eye-hand alignment, and then consider how head orientation influences the linkage between oculocentric visual frames and bodycentric motor frames. These findings are framed in terms of our 'conversion-on-demand' model, which suggests a virtual representation of egocentric space, i.e. one in which only those representations selected for action are put through the complex visuomotor transformations required for interaction with actual objects in personal space.

  6. Ocular kinematics and eye-hand coordination.

    PubMed

    Crawford, J D; Henriques, D Y P; Medendorp, W P; Khan, A Z

    2003-03-01

    Eye-hand coordination is complicated by the fact that the eyes are constantly in motion relative to the head. This poses problems in interpreting the spatial information gathered from the retinas and using this to guide hand motion. In particular, eye-centered visual information must somehow be spatially updated across eye movements to be useful for future actions, and these representations must then be transformed into commands appropriate for arm motion. In this review, we present evidence that early visuomotor representations for arm movement are remapped relative to the gaze direction during each saccade. We find that this mechanism holds for targets in both far and near visual space. We then show how the brain incorporates the three-dimensional, rotary geometry of the eyes when interpreting retinal images and transforming these into commands for arm movement. Next, we explore the possibility that hand-eye alignment is optimized for the eye with the best field of view. Finally, we describe how head orientation influences the linkage between oculocentric visual frames and bodycentric motor frames. These findings are framed in terms of our 'conversion-on-demand' model, in which only those representations selected for action are put through the complex visuomotor transformations required for interaction with objects in personal space, thus providing a virtual on-line map of visuomotor space.

  7. Hand-Eye Coordination Predicts Joint Attention.

    PubMed

    Yu, Chen; Smith, Linda B

    2017-02-10

    The present article shows that infant and dyad differences in hand-eye coordination predict dyad differences in joint attention (JA). In the study reported here, 51 toddlers ranging in age from 11 to 24 months and their parents wore head-mounted eye trackers as they played with objects together. We found that physically active toddlers aligned their looking behavior with their parent and achieved a substantial proportion of time spent jointly attending to the same object. However, JA did not arise through gaze following but rather through the coordination of gaze with manual actions on objects as both infants and parents attended to their partner's object manipulations. Moreover, dyad differences in JA were associated with dyad differences in hand following.

  8. Lags in measuring eye-hand coordination.

    PubMed

    Hill, Liam J B; Culmer, Peter R; Mon-Williams, Mark

    2014-07-30

    We challenge a number of the claims for novelty and innovation made in a recent published paper (Lee et al., 2014) with regard to a computerised methodology that these authors present for assessing eye-hand coordination (EHC). Published work on similar pre-existing computerised systems is discussed and arguments made for these alternative systems being equal, if not superior, in terms of their innovativeness. The commentary does not dispute the usefulness of systems such as the one described by Lee et al. Rather, in the interests of scholarship it provides an accompanying insight into the significant scholarly contributions previously, and contemporaneously, being made by other research groups working in this area.

  9. Coordinated Flexibility: How Initial Gaze Position Modulates Eye-Hand Coordination and Reaching

    ERIC Educational Resources Information Center

    Adam, Jos J.; Buetti, Simona; Kerzel, Dirk

    2012-01-01

    Reaching to targets in space requires the coordination of eye and hand movements. In two experiments, we recorded eye and hand kinematics to examine the role of gaze position at target onset on eye-hand coordination and reaching performance. Experiment 1 showed that with eyes and hand aligned on the same peripheral start location, time lags…

  10. Coordinated Flexibility: How Initial Gaze Position Modulates Eye-Hand Coordination and Reaching

    ERIC Educational Resources Information Center

    Adam, Jos J.; Buetti, Simona; Kerzel, Dirk

    2012-01-01

    Reaching to targets in space requires the coordination of eye and hand movements. In two experiments, we recorded eye and hand kinematics to examine the role of gaze position at target onset on eye-hand coordination and reaching performance. Experiment 1 showed that with eyes and hand aligned on the same peripheral start location, time lags…

  11. Evidence of common and separate eye and hand accumulators underlying flexible eye-hand coordination.

    PubMed

    Jana, Sumitash; Gopal, Atul; Murthy, Aditya

    2017-01-01

    Eye and hand movements are initiated by anatomically separate regions in the brain, and yet these movements can be flexibly coupled and decoupled, depending on the need. The computational architecture that enables this flexible coupling of independent effectors is not understood. Here, we studied the computational architecture that enables flexible eye-hand coordination using a drift diffusion framework, which predicts that the variability of the reaction time (RT) distribution scales with its mean. We show that a common stochastic accumulator to threshold, followed by a noisy effector-dependent delay, explains eye-hand RT distributions and their correlation in a visual search task that required decision-making, while an interactive eye and hand accumulator model did not. In contrast, in an eye-hand dual task, an interactive model better predicted the observed correlations and RT distributions than a common accumulator model. Notably, these two models could only be distinguished on the basis of the variability and not the means of the predicted RT distributions. Additionally, signatures of separate initiation signals were also observed in a small fraction of trials in the visual search task, implying that these distinct computational architectures were not a manifestation of the task design per se. Taken together, our results suggest two unique computational architectures for eye-hand coordination, with task context biasing the brain toward instantiating one of the two architectures. Previous studies on eye-hand coordination have considered mainly the means of eye and hand reaction time (RT) distributions. Here, we leverage the approximately linear relationship between the mean and standard deviation of RT distributions, as predicted by the drift-diffusion model, to propose the existence of two distinct computational architectures underlying coordinated eye-hand movements. These architectures, for the first time, provide a computational basis for the flexible

  12. Eye-hand coordination in object manipulation.

    PubMed

    Johansson, R S; Westling, G; Bäckström, A; Flanagan, J R

    2001-09-01

    We analyzed the coordination between gaze behavior, fingertip movements, and movements of the manipulated object when subjects reached for and grasped a bar and moved it to press a target-switch. Subjects almost exclusively fixated certain landmarks critical for the control of the task. Landmarks at which contact events took place were obligatory gaze targets. These included the grasp site on the bar, the target, and the support surface where the bar was returned after target contact. Any obstacle in the direct movement path and the tip of the bar were optional landmarks. Subjects never fixated the hand or the moving bar. Gaze and hand/bar movements were linked concerning landmarks, with gaze leading. The instant that gaze exited a given landmark coincided with a kinematic event at that landmark in a manner suggesting that subjects monitored critical kinematic events for phasic verification of task progress and subgoal completion. For both the obstacle and target, subjects directed saccades and fixations to sites that were offset from the physical extension of the objects. Fixations related to an obstacle appeared to specify a location around which the extending tip of the bar should travel. We conclude that gaze supports hand movement planning by marking key positions to which the fingertips or grasped object are subsequently directed. The salience of gaze targets arises from the functional sensorimotor requirements of the task. We further suggest that gaze control contributes to the development and maintenance of sensorimotor correlation matrices that support predictive motor control in manipulation.

  13. Eye hand coordination in children with cerebral palsy.

    PubMed

    Saavedra, Sandra; Joshi, Aditi; Woollacott, Marjorie; van Donkelaar, Paul

    2009-01-01

    Reaching to grasp an object of interest requires complex sensorimotor coordination involving eye, head, hand and trunk. While numerous studies have demonstrated deficits in each of these systems individually, little is known about how children with cerebral palsy (CP) coordinate multiple motor systems for functional tasks. Here we used kinematics, remote eye tracking and a trunk support device to examine the functional coupling of the eye, head and hand and the extent to which it was constrained by trunk postural control in 10 children with CP (6-16 years). Eye movements in children with CP were similar to typically developing (TD) peers, while hand movements were significantly slower. Postural support influenced initiation of hand movements in the youngest children (TD & CP) and execution of hand movements in children with CP differentially depending on diagnosis. Across all diagnostic categories, the most robust distinction between TD children and children with CP was in their ability to isolate eye, head and hand movements. Results of this study suggest that deficits in motor coordination for accurate reaching in children with CP may reflect coupled eye, head, and hand movements. We have previously suggested that coupled activation of effectors may be the default output for the CNS during early development.

  14. Eye-Hand-Mouth Coordination in the Human Newborn.

    PubMed

    Futagi, Yasuyuki

    2017-10-01

    There have been several studies concerning rudimentary coordination of the eyes, hands, and mouth in the human newborn. The author attempted to clarify the ontogenetic significance of the coordination during the earliest period of human life through a systematic review. The neural mechanism underlying the coordination was also discussed based on the current knowledge of cognitive neuroscience. Searches were conducted on PubMed and Google Scholar from their inception through March 2017. Studies have demonstrated that the coordination is a visually guided goal-directed motor behavior with intension and emotion. Current cognitive research has proved that feeding requires a large-scale neural network extending over several cortices. The eye-hand-mouth coordination in the newborn can be regarded as a precursor of subsequent self-feeding, and the coordination is very likely mediated through the underdeveloped but essentially the same network interconnecting cortices as in the adult. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Tactile VR for hand-eye coordination in simulated PTCA.

    PubMed

    Cai, Y Y; Chui, C K; Ye, X Z; Fan, Z; Anderson, J H

    2006-02-01

    Percutaneous transluminal coronary angioplasty (PTCA) is a minimally invasive image-guided technique for treatment of coronary diseases. PTCA procedure requires physicians to have good skills of hand-eye coordination in performing the operation. Training of PTCA thus very much emphasizes skill building for hand-eye coordination. We have been developing virtual reality (VR) technology for medical simulation. In this paper, we will address the issue of VR-based simulation for the enhancement of hand-eye coordination for PTCA operation. Starting from the characterization of PTCA procedure, we examine what roles VR can play in training of PTCA physicians. We then describe a computerized PTCA training system we have developed which is composed of a tactile interface and a visual interface. The system is designed in such a way that real PTCA devices (including catheters and guide-wires) can be used to mimic the requirements of the CathLab. The backend computational engine supporting the real-time and realistic PTCA simulation is also presented.

  16. Balance reactions and eye-hand coordination in idiopathic scoliosis.

    PubMed

    Adler, N; Bleck, E E; Rinsky, L A; Young, W

    1986-01-01

    We undertook this study to determine if subclinical postural control mechanisms were abnormal in idiopathic scoliosis. Ninety-one female patients and fifty-seven age-matched female controls were examined. We used a force plate ataxiometer to quantitate postural sway in the standing position and recorded the displacement and acceleration of the center of pressure during static stance and under perturbation with eyes opened and closed. A joystick-controlled video system was used to measure reaction time and eye-hand motor coordination. The scoliosis group demonstrated significantly less sway during two of the eight standing balance conditions and on the remaining balance tests there was a similar trend, albeit nonsignificant. The reaction time for the scoliosis group was also significantly slower, but the accuracy was not significantly worse. We noted no statistical differences between progressive and nonprogressive or between braced and unbraced patients. The subgroup of patients whose curves progressed despite bracing had a tendency to demonstrate greater stability on all standing tests. They also exhibited faster reaction times and less error in eye-hand coordination than other patient groups. No correlation existed between severity of curve and test performance. We found no indication of deficient balance in idiopathic scoliosis, and the tests could not predict curve progression.

  17. Interaction between the premotor processes of eye and hand movements: possible mechanism underlying eye-hand coordination.

    PubMed

    Hiraoka, Koichi; Kurata, Naoatsu; Sakaguchi, Masato; Nonaka, Kengo; Matsumoto, Naoto

    2014-03-01

    Interaction between the execution process of eye movement and that of hand movement must be indispensable for eye-hand coordination. The present study investigated corticospinal excitability in the hand muscles during the premotor processes of eye and/or hand movement to elucidate interaction between these processes. Healthy humans performed a precued reaction task of eye and/or finger movement and motor-evoked potentials in the hand muscles were evoked in the reaction time. Leftward eye movement suppressed corticospinal excitability in the right abductor digiti minimi muscle only when little finger abduction was simultaneously executed. Corticospinal excitability in the first dorsal interosseous muscle was not suppressed by eye movement regardless of whether or not it was accompanied by finger movement. Suppression of corticospinal excitability in the hand muscles induced by eye movement in the premotor period depends on the direction of eye movement, the muscle tested, and the premotor process of the tested muscle. The suppression may reflect interaction between the motor process of eye movement and that of hand movement particularly active during eye-hand coordination tasks during which both processes proceed.

  18. Hand preference consistency and eye-hand coordination in young children during a motor task.

    PubMed

    Mori, Shiro; Iteya, Misaki; Gabbard, Carl

    2006-02-01

    Indications of earlier research are that individuals exhibiting a consistent hand preference are better coordinated on selected motor tasks than peers with inconsistent hand preference. The present study examined eye-hand coordination via inter- and intramodal matching behavior by handedness groups for 55 5- and 6-yr.-olds using the Pinboard Test. Analysis indicated the Consistent group scored better, leading to the speculation that children with consistent laterality may possess an advantage in interhemispheric communication, especially when the task requires coordination of both limbs.

  19. Effects of hand termination and accuracy requirements on eye-hand coordination in older adults

    PubMed Central

    Rand, Miya K.; Stelmach, George E.

    2010-01-01

    This study investigated how aging compromises the control of saccades and eye-hand coordination when accuracy constraints and termination requirements of hand movement are altered. Seventeen older adults and seventeen young controls performed two-segment aiming movements. The first segment had two target sizes to alter accuracy constraints. Two-segment eye movements were always made to first and second targets, whereas hand movements were varied across three hand-movement types with different termination requirements: 1) stop both at the first and second targets, 2) stop at the first target and discontinue, and 3) move through the first target and discontinue. Compared to the young adults, the older adults produced hypometric primary saccades and delayed gaze fixation to the first target. The older adults also modified eye movements less depending on the hand termination and accuracy requirements. After pointing completion to the first target, the older adults maintained their gaze fixation to that target for a longer duration than young adults. However, this prolonged gaze fixation was minimized when a hand termination was not required. Conversely, the prolongation of gaze fixation was magnified when the hand termination was required at the first target while the eye movement was continuing to the next target. Thus, older adults have difficulties in concurrent control of inhibiting hand movement and initiating eye movement at a target within a sequence. Taken together, it is suggested that aging reduces the ability to modify eye movements to meet various behavioral constraints imposed on manual aiming tasks. PMID:21163306

  20. RECOGNIZING BEHAVIOR IN HAND-EYE COORDINATION PATTERNS

    PubMed Central

    Yi, Weilie; Ballard, Dana

    2010-01-01

    Modeling human behavior is important for the design of robots as well as human-computer interfaces that use humanoid avatars. Constructive models have been built, but they have not captured all of the detailed structure of human behavior such as the moment-to-moment deployment and coordination of hand, head and eye gaze used in complex tasks. We show how this data from human subjects performing a task can be used to program a dynamic Bayes network (DBN) which in turn can be used to recognize new performance instances. As a specific demonstration we show that the steps in a complex activity such as sandwich making can be recognized by a DBN in real time. PMID:20862267

  1. Eye-hand coordination during a double-step task: evidence for a common stochastic accumulator

    PubMed Central

    Gopal, Atul

    2015-01-01

    Many studies of reaching and pointing have shown significant spatial and temporal correlations between eye and hand movements. Nevertheless, it remains unclear whether these correlations are incidental, arising from common inputs (independent model); whether these correlations represent an interaction between otherwise independent eye and hand systems (interactive model); or whether these correlations arise from a single dedicated eye-hand system (common command model). Subjects were instructed to redirect gaze and pointing movements in a double-step task in an attempt to decouple eye-hand movements and causally distinguish between the three architectures. We used a drift-diffusion framework in the context of a race model, which has been previously used to explain redirect behavior for eye and hand movements separately, to predict the pattern of eye-hand decoupling. We found that the common command architecture could best explain the observed frequency of different eye and hand response patterns to the target step. A common stochastic accumulator for eye-hand coordination also predicts comparable variances, despite significant difference in the means of the eye and hand reaction time (RT) distributions, which we tested. Consistent with this prediction, we observed that the variances of the eye and hand RTs were similar, despite much larger hand RTs (∼90 ms). Moreover, changes in mean eye RTs, which also increased eye RT variance, produced a similar increase in mean and variance of the associated hand RT. Taken together, these data suggest that a dedicated circuit underlies coordinated eye-hand planning. PMID:26084906

  2. A common stochastic accumulator with effector-dependent noise can explain eye-hand coordination

    PubMed Central

    Gopal, Atul; Viswanathan, Pooja

    2015-01-01

    The computational architecture that enables the flexible coupling between otherwise independent eye and hand effector systems is not understood. By using a drift diffusion framework, in which variability of the reaction time (RT) distribution scales with mean RT, we tested the ability of a common stochastic accumulator to explain eye-hand coordination. Using a combination of behavior, computational modeling and electromyography, we show how a single stochastic accumulator to threshold, followed by noisy effector-dependent delays, explains eye-hand RT distributions and their correlation, while an alternate independent, interactive eye and hand accumulator model does not. Interestingly, the common accumulator model did not explain the RT distributions of the same subjects when they made eye and hand movements in isolation. Taken together, these data suggest that a dedicated circuit underlies coordinated eye-hand planning. PMID:25568161

  3. Eye-hand coordination during a double-step task: evidence for a common stochastic accumulator.

    PubMed

    Gopal, Atul; Murthy, Aditya

    2015-09-01

    Many studies of reaching and pointing have shown significant spatial and temporal correlations between eye and hand movements. Nevertheless, it remains unclear whether these correlations are incidental, arising from common inputs (independent model); whether these correlations represent an interaction between otherwise independent eye and hand systems (interactive model); or whether these correlations arise from a single dedicated eye-hand system (common command model). Subjects were instructed to redirect gaze and pointing movements in a double-step task in an attempt to decouple eye-hand movements and causally distinguish between the three architectures. We used a drift-diffusion framework in the context of a race model, which has been previously used to explain redirect behavior for eye and hand movements separately, to predict the pattern of eye-hand decoupling. We found that the common command architecture could best explain the observed frequency of different eye and hand response patterns to the target step. A common stochastic accumulator for eye-hand coordination also predicts comparable variances, despite significant difference in the means of the eye and hand reaction time (RT) distributions, which we tested. Consistent with this prediction, we observed that the variances of the eye and hand RTs were similar, despite much larger hand RTs (∼90 ms). Moreover, changes in mean eye RTs, which also increased eye RT variance, produced a similar increase in mean and variance of the associated hand RT. Taken together, these data suggest that a dedicated circuit underlies coordinated eye-hand planning. Copyright © 2015 the American Physiological Society.

  4. Repeatability of the timing of eye-hand coordinated movements across different cognitive tasks.

    PubMed

    de Boer, C; van der Steen, J; Schol, R J; Pel, J J M

    2013-08-15

    Quantification of eye-hand coordinated behaviour is a relatively new tool to study neurodegeneration in humans. Its sensitivity depends on the assessment of different behavioural strategies, multiple task testing and repeating tasks within one session. However, large numbers of repetition trials pose a significant burden on subjects. To introduce this method in large-scale population studies, it is necessary to determine whether reducing the number of task repetitions, which will lower subject burden, still leads to acceptable measurement accuracy. The objective of this study was to investigate the validity and reliability of eye-hand coordination outcome parameters in eight healthy volunteers using a test-retest approach. Subjects were assessed during a shortened test procedure consisting of eight repetitions of three behavioural tasks: a reflex-based tapping task, a planning-based tapping task and a memory-based tapping task. Eye-hand coordination was quantified in terms of timing (eye and hand latencies), kinematics and accuracy. Eye and hand latencies were found within a normal range (between 150 and 450ms). A paired samples t-test revealed no differences in timing parameters between the first and second measurements. It was concluded that eight trial repetitions are sufficient for quantifying eye-hand coordination in terms of timing, kinematics and accuracy. This approach demonstrates the testing of multiple visuomotor behaviours within a reasonable time span of a few minutes per task.

  5. Eye-Hand Coordination during Dynamic Visuomotor Rotations

    PubMed Central

    Masia, Lorenzo; Casadio, Maura; Sandini, Giulio; Morasso, Pietro

    2009-01-01

    Background for many technology-driven visuomotor tasks such as tele-surgery, human operators face situations in which the frames of reference for vision and action are misaligned and need to be compensated in order to perform the tasks with the necessary precision. The cognitive mechanisms for the selection of appropriate frames of reference are still not fully understood. This study investigated the effect of changing visual and kinesthetic frames of reference during wrist pointing, simulating activities typical for tele-operations. Methods using a robotic manipulandum, subjects had to perform center-out pointing movements to visual targets presented on a computer screen, by coordinating wrist flexion/extension with abduction/adduction. We compared movements in which the frames of reference were aligned (unperturbed condition) with movements performed under different combinations of visual/kinesthetic dynamic perturbations. The visual frame of reference was centered to the computer screen, while the kinesthetic frame was centered around the wrist joint. Both frames changed their orientation dynamically (angular velocity = 36°/s) with respect to the head-centered frame of reference (the eyes). Perturbations were either unimodal (visual or kinesthetic), or bimodal (visual+kinesthetic). As expected, pointing performance was best in the unperturbed condition. The spatial pointing error dramatically worsened during both unimodal and most bimodal conditions. However, in the bimodal condition, in which both disturbances were in phase, adaptation was very fast and kinematic performance indicators approached the values of the unperturbed condition. Conclusions this result suggests that subjects learned to exploit an “affordance” made available by the invariant phase relation between the visual and kinesthetic frames. It seems that after detecting such invariance, subjects used the kinesthetic input as an informative signal rather than a disturbance, in order to

  6. Modeling and evaluation of hand-eye coordination of surgical robotic system on task performance.

    PubMed

    Gao, Yuanqian; Wang, Shuxin; Li, Jianmin; Li, Aimin; Liu, Hongbin; Xing, Yuan

    2017-05-04

    Robotic-assisted minimally invasive surgery changes the direct hand and eye coordination in traditional surgery to indirect instrument and camera coordination, which affects the ergonomics, operation performance, and safety. A camera, two instruments, and a target, as the descriptors, are used to construct the workspace correspondence and geometrical relationships in a surgical operation. A parametric model with a set of parameters is proposed to describe the hand-eye coordination of the surgical robot. From the results, optimal values and acceptable ranges of these parameters are identified from two tasks. A 90° viewing angle had the longest completion time; 60° instrument elevation angle and 0° deflection angle had better performance; there is no significant difference among manipulation angles and observing distances on task performance. This hand-eye coordination model provides evidence for robotic design, surgeon training, and robotic initialization to achieve dexterous and safe manipulation in surgery. Copyright © 2017 John Wiley & Sons, Ltd.

  7. Movement-related activity in the periarcuate cortex of monkeys during coordinated eye and hand movements.

    PubMed

    Kurata, Kiyoshi

    2017-09-20

    To determine the role of the periarcuate cortex during coordinated eye and hand movements in monkeys, the present study examined neuronal activity in this region during movement with the hand, eyes, or both as effectors toward a visuospatial target. Similar to the primary motor cortex (M1), the dorsal premotor cortex contained a higher proportion of neurons that were closely related to hand movements, whereas saccade-related neurons were frequently recorded from the frontal eye field (FEF). Interestingly, neurons that exhibited activity related to both eye and hand movements were recorded most frequently in the ventral premotor cortex (PMv), located between the FEF and M1. Neuronal activity in the periarcuate cortex was highly modulated during coordinated movements compared to either eye or hand movement only. Additionally, a small number of neurons were active specifically during one of the three task modes, which could be dissociated from the effector activity. In this case, neuron onset was either ahead of or behind the onset of eye and/or hand movement, and some neuronal activity lasted until reward delivery signaled successful completion of reaching. The present findings indicate that the periarcuate cortex, particularly the PMv, plays important roles in orchestrating coordinated movements from the initiation to the termination of reaching. Copyright © 2017, Journal of Neurophysiology.

  8. Mahjong playing and eye-hand coordination in older adults—a cross-sectional study

    PubMed Central

    Tsang, William W.N.; Wong, Gloria C.K.; Gao, Kelly L.

    2016-01-01

    [Purpose] Eye-hand coordination declines with age, but physical activity is known to slow down the degeneration. Playing mahjong involves lots of eye-hand coordination. The objective was to investigate the relationship between playing mahjong and eye-hand coordination in older adults using a fast finger-pointing paradigm. [Subjects and Methods] Forty-one community dwelling older adults aged sixty or above were recruited by convenience sampling in this cross-sectional study. They were tested on their ability to point quickly and accurately 1) toward a stationary visual target and 2) toward a moving visual target. [Results] The mahjong players demonstrated significantly better end-point accuracy when pointing with their non-dominant hand toward a stationary target. They also demonstrated significantly faster movement of their dominant hands; shorter reaction times and better end-point accuracy when pointing with their non-dominant hands toward a moving target. [Conclusion] Mahjong players have better eye-hand coordination than non-players. Playing mahjong could usefully be introduced to older adults as a leisure time activity. PMID:27821969

  9. The Contribution of Different Cortical Regions to the Control of Spatially Decoupled Eye-Hand Coordination.

    PubMed

    Sayegh, Patricia F; Gorbet, Diana J; Hawkins, Kara M; Hoffman, Kari L; Sergio, Lauren E

    2017-03-02

    Our brain's ability to flexibly control the communication between the eyes and the hand allows for our successful interaction with the objects located within our environment. This flexibility has been observed in the pattern of neural responses within key regions of the frontoparietal reach network. More specifically, our group has shown how single-unit and oscillatory activity within the dorsal premotor cortex (PMd) and the superior parietal lobule (SPL) change contingent on the level of visuomotor compatibility between the eyes and hand. Reaches that involve a coupling between the eyes and hand toward a common spatial target display a pattern of neural responses that differ from reaches that require eye-hand decoupling. Although previous work examined the altered spiking and oscillatory activity that occurs during different types of eye-hand compatibilities, they did not address how each of these measures of neurological activity interacts with one another. Thus, in an effort to fully characterize the relationship between oscillatory and single-unit activity during different types of eye-hand coordination, we measured the spike-field coherence (SFC) within regions of macaque SPL and PMd. We observed stronger SFC within PMdr and superficial regions of SPL (areas 5/PEc) during decoupled reaches, whereas PMdc and regions within SPL surrounding medial intrapareital sulcus had stronger SFC during coupled reaches. These results were supported by meta-analysis on human fMRI data. Our results support the proposal of altered cortical control during complex eye-hand coordination and highlight the necessity to account for the different eye-hand compatibilities in motor control research.

  10. Both age and physical activity level impact on eye-hand coordination.

    PubMed

    Van Halewyck, Florian; Lavrysen, Ann; Levin, Oron; Boisgontier, Matthieu P; Elliott, Digby; Helsen, Werner F

    2014-08-01

    Aging impacts on our ability to perform goal-directed aiming movements. Older adults generally make slower and shorter initial impulses towards the end target, and therefore require more time for corrections in the final movement stage. Recent studies however suggest that a physically active lifestyle may attenuate these age-related changes. Also, it remains unclear whether eye-movement control exhibits a similar pattern of adaptation in older adults. Therefore, the first aim of this study was to describe how age and physical activity level impact eye-hand coordination during discrete manual aiming. Young and older participants were divided into physically active and sedentary subgroups, and performed discrete aiming movements while hand and eye movements were recorded. Secondly, to determine whether older adults depend more on vision during aiming, the task was repeated without visual feedback. The results revealed that the typical age-related hand movement adaptations were not only observed in older, but also in sedentary young participants. Older and sedentary young participants also spent more hand movement time after the eyes fixated the end target. This finding does not necessarily reflect an augmented reliance on vision, as all groups showed similar aiming errors when visual feedback was removed. In conclusion, both age and physical activity level clearly impacted eye-hand coordination during discrete manual aiming. This adapted coordination pattern seems to be caused by other factors than an increased reliance on vision.

  11. Hand/Eye Coordination For Fine Robotic Motion

    NASA Technical Reports Server (NTRS)

    Lokshin, Anatole M.

    1992-01-01

    Fine motions of robotic manipulator controlled with help of visual feedback by new method reducing position errors by order of magnitude. Robotic vision subsystem includes five cameras: three stationary ones providing wide-angle views of workspace and two mounted on wrist of auxiliary robot arm. Stereoscopic cameras on arm give close-up views of object and end effector. Cameras measure errors between commanded and actual positions and/or provide data for mapping between visual and manipulator-joint-angle coordinates.

  12. Joint attention without gaze following: human infants and their parents coordinate visual attention to objects through eye-hand coordination.

    PubMed

    Yu, Chen; Smith, Linda B

    2013-01-01

    The coordination of visual attention among social partners is central to many components of human behavior and human development. Previous research has focused on one pathway to the coordination of looking behavior by social partners, gaze following. The extant evidence shows that even very young infants follow the direction of another's gaze but they do so only in highly constrained spatial contexts because gaze direction is not a spatially precise cue as to the visual target and not easily used in spatially complex social interactions. Our findings, derived from the moment-to-moment tracking of eye gaze of one-year-olds and their parents as they actively played with toys, provide evidence for an alternative pathway, through the coordination of hands and eyes in goal-directed action. In goal-directed actions, the hands and eyes of the actor are tightly coordinated both temporally and spatially, and thus, in contexts including manual engagement with objects, hand movements and eye movements provide redundant information about where the eyes are looking. Our findings show that one-year-olds rarely look to the parent's face and eyes in these contexts but rather infants and parents coordinate looking behavior without gaze following by attending to objects held by the self or the social partner. This pathway, through eye-hand coupling, leads to coordinated joint switches in visual attention and to an overall high rate of looking at the same object at the same time, and may be the dominant pathway through which physically active toddlers align their looking behavior with a social partner.

  13. Sequence for the Training of Eye-Hand Coordination Needed for the Organization of Handwriting Tasks

    ERIC Educational Resources Information Center

    Trester, Mary Fran

    1971-01-01

    Suggested is a sequence of 11 class activities, progressing from gross to fine motor skills, to assist the development of skills required to perform handwriting tasks successfully, for use particularly with children who lack fine motor control and eye-hand coordination. (KW)

  14. Effect of Participation in a Cup Stacking Unit on Hand-Eye Coordination of Elementary Children

    ERIC Educational Resources Information Center

    Hart, Melanie A.; Smith, Lori A.; DeChant-Bruennig, Ann

    2006-01-01

    The purpose of this study was to empirically examine the influence of a cup stacking instructional unit on the hand-eye coordination of children. Participants (N = 104) consisted of three grade level groups (first/second, third and fourth). Within each grade level participants were randomly assigned to either an experimental or a control group.…

  15. Sequence for the Training of Eye-Hand Coordination Needed for the Organization of Handwriting Tasks

    ERIC Educational Resources Information Center

    Trester, Mary Fran

    1971-01-01

    Suggested is a sequence of 11 class activities, progressing from gross to fine motor skills, to assist the development of skills required to perform handwriting tasks successfully, for use particularly with children who lack fine motor control and eye-hand coordination. (KW)

  16. Effect of Participation in a Cup Stacking Unit on Hand-Eye Coordination of Elementary Children

    ERIC Educational Resources Information Center

    Hart, Melanie A.; Smith, Lori A.; DeChant-Bruennig, Ann

    2006-01-01

    The purpose of this study was to empirically examine the influence of a cup stacking instructional unit on the hand-eye coordination of children. Participants (N = 104) consisted of three grade level groups (first/second, third and fourth). Within each grade level participants were randomly assigned to either an experimental or a control group.…

  17. The effects of monocular viewing on hand-eye coordination during sequential grasping and placing movements.

    PubMed

    Gonzalez, David A; Niechwiej-Szwedo, Ewa

    2016-11-01

    The contribution of binocular vision to the performance of reaching and grasping movements has been examined previously using single reach-to-grasp movements. However, most of our daily activities consist of more complex action sequences, which require precise temporal linking between the gaze behaviour and manual action phases. Many previous studies found a stereotypical hand-eye coordination pattern, such that the eyes move prior to the reach initiation. Moving the eyes to the target object provides information about its features and location, which can facilitate the predictive control of reaching and grasping. This temporal coordination pattern has been established for the performance of sequential movements performed during binocular viewing. Here we manipulated viewing condition and examined the temporal hand-eye coordination pattern during the performance of a sequential reaching, grasping, and placement task. Fifteen participants were tested on a sequencing task while eye and hand movements were recorded binocularly using a video-based eyetracker and a motion capture system. Our results showed that monocular viewing disrupted the temporal coordination between the eyes and the hand during the place-to-reach transition phase. Specifically, the gaze shift was delayed during monocular compared to binocular viewing. The shift in gaze behaviour may be due to increased uncertainty associated with the performance of the placement task because of increased vergence error during monocular viewing, which was evident in all participants. These findings provide insight into the role of binocular vision in predictive control of sequential reaching and grasping movements. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. The optic chiasm: a turning point in the evolution of eye/hand coordination

    PubMed Central

    2013-01-01

    The primate visual system has a uniquely high proportion of ipsilateral retinal projections, retinal ganglial cells that do not cross the midline in the optic chiasm. The general assumption is that this developed due to the selective advantage of accurate depth perception through stereopsis. Here, the hypothesis that the need for accurate eye-forelimb coordination substantially influenced the evolution of the primate visual system is presented. Evolutionary processes may change the direction of retinal ganglial cells. Crossing, or non-crossing, in the optic chiasm determines which hemisphere receives visual feedback in reaching tasks. Each hemisphere receives little tactile and proprioceptive information about the ipsilateral hand. The eye-forelimb hypothesis proposes that abundant ipsilateral retinal projections developed in the primate brain to synthesize, in a single hemisphere, visual, tactile, proprioceptive, and motor information about a given hand, and that this improved eye-hand coordination and optimized the size of the brain. If accurate eye-hand coordination was a major factor in the evolution of stereopsis, stereopsis is likely to be highly developed for activity in the area where the hands most often operate. The primate visual system is ideally suited for tasks within arm’s length and in the inferior visual field, where most manual activity takes place. Altering of ocular dominance in reaching tasks, reduced cross-modal cuing effects when arms are crossed, response of neurons in the primary motor cortex to viewed actions of a hand, multimodal neuron response to tactile as well as visual events, and extensive use of multimodal sensory information in reaching maneuvers support the premise that benefits of accurate limb control influenced the evolution of the primate visual system. The eye-forelimb hypothesis implies that evolutionary change toward hemidecussation in the optic chiasm provided parsimonious neural pathways in animals developing frontal

  19. The optic chiasm: a turning point in the evolution of eye/hand coordination.

    PubMed

    Larsson, Matz

    2013-07-18

    The primate visual system has a uniquely high proportion of ipsilateral retinal projections, retinal ganglial cells that do not cross the midline in the optic chiasm. The general assumption is that this developed due to the selective advantage of accurate depth perception through stereopsis. Here, the hypothesis that the need for accurate eye-forelimb coordination substantially influenced the evolution of the primate visual system is presented. Evolutionary processes may change the direction of retinal ganglial cells. Crossing, or non-crossing, in the optic chiasm determines which hemisphere receives visual feedback in reaching tasks. Each hemisphere receives little tactile and proprioceptive information about the ipsilateral hand. The eye-forelimb hypothesis proposes that abundant ipsilateral retinal projections developed in the primate brain to synthesize, in a single hemisphere, visual, tactile, proprioceptive, and motor information about a given hand, and that this improved eye-hand coordination and optimized the size of the brain. If accurate eye-hand coordination was a major factor in the evolution of stereopsis, stereopsis is likely to be highly developed for activity in the area where the hands most often operate.The primate visual system is ideally suited for tasks within arm's length and in the inferior visual field, where most manual activity takes place. Altering of ocular dominance in reaching tasks, reduced cross-modal cuing effects when arms are crossed, response of neurons in the primary motor cortex to viewed actions of a hand, multimodal neuron response to tactile as well as visual events, and extensive use of multimodal sensory information in reaching maneuvers support the premise that benefits of accurate limb control influenced the evolution of the primate visual system. The eye-forelimb hypothesis implies that evolutionary change toward hemidecussation in the optic chiasm provided parsimonious neural pathways in animals developing frontal

  20. Influence of cup stacking on hand-eye coordination and reaction time of second-grade students.

    PubMed

    Udermann, Brian E; Murray, Steven R; Mayer, John M; Sagendorf, Kenneth

    2004-04-01

    Cup stacking has been adopted recently by many physical education programs to enhance rudimentary motor skills such as hand-eye coordination and ambidexterity as well as quickness and concentration; however, no empirical evidence has been published to support these claims. We examined the influence of cup stacking on hand-eye coordination and reaction time of 24 boys and 18 girls in second grade as measured by the Soda Pop and Yardstick tests, respectively. Two physical education classes were randomly assigned as treatment and control groups and were pre- and posttested for hand-eye coordination and reaction time. The treatment group participated in a 5-wk. cup-stacking program. Significant improvements were noted for both hand-eye coordination and reaction time between the pre- and posttest scores for this group but not for the control group. Therefore, cup stacking is indeed effective in enhancing hand-eye coordination and reaction time.

  1. Eye-Hand Coordination during Visuomotor Adaptation with Different Rotation Angles

    PubMed Central

    Rentsch, Sebastian; Rand, Miya K.

    2014-01-01

    This study examined adaptive changes of eye-hand coordination during a visuomotor rotation task. Young adults made aiming movements to targets on a horizontal plane, while looking at the rotated feedback (cursor) of hand movements on a monitor. To vary the task difficulty, three rotation angles (30°, 75°, and 150°) were tested in three groups. All groups shortened hand movement time and trajectory length with practice. However, control strategies used were different among groups. The 30° group used proportionately more implicit adjustments of hand movements than other groups. The 75° group used more on-line feedback control, whereas the 150° group used explicit strategic adjustments. Regarding eye-hand coordination, timing of gaze shift to the target was gradually changed with practice from the late to early phase of hand movements in all groups, indicating an emerging gaze-anchoring behavior. Gaze locations prior to the gaze anchoring were also modified with practice from the cursor vicinity to an area between the starting position and the target. Reflecting various task difficulties, these changes occurred fastest in the 30° group, followed by the 75° group. The 150° group persisted in gazing at the cursor vicinity. These results suggest that the function of gaze control during visuomotor adaptation changes from a reactive control for exploring the relation between cursor and hand movements to a predictive control for guiding the hand to the task goal. That gaze-anchoring behavior emerged in all groups despite various control strategies indicates a generality of this adaptive pattern for eye-hand coordination in goal-directed actions. PMID:25333942

  2. Effects of induced monocular blur versus anisometropic amblyopia on saccades, reaching, and eye-hand coordination.

    PubMed

    Niechwiej-Szwedo, Ewa; Kennedy, Sean A; Colpa, Linda; Chandrakumar, Manokaraananthan; Goltz, Herbert C; Wong, Agnes M F

    2012-07-01

    We previously showed that anisometropic amblyopia affects the programming and execution of saccades and reaching movements. In our current study, we investigated whether these amblyopia-related changes simply are due to a reduction in visual acuity alone by inducing artificial blur in one eye in visually-normal participants. Twelve visually-normal participants performed saccades and reach-to-touch movements to targets presented on a computer screen during binocular and monocular viewing. A contact lens was used to blur the vision of one eye to a mean acuity level of 20/50. Saccades and reaching kinematics were compared before blur, immediately after blur, and 5 hours after blur was induced. The 5 hours after blur kinematic data from visually-normal participants also were compared to those from 12 patients with anisometropic amblyopia who had comparable acuity in the amblyopic eye. Primary saccades (latency, amplitude, peak velocity), reaching movements (reaction time, movement time, peak acceleration, duration of the acceleration phase), and eye-hand coordination (saccade-to-reach planning interval, saccade-to-reach peak velocity interval) were not affected by induced monocular blur in visually-normal participants, either immediately or 5 hours after blur. Compared to visually-normal participants after 5 hours of blur, patients with anisometropic amblyopia had significantly longer and more variable saccade latency during amblyopic eye viewing, lower peak acceleration, and a longer acceleration phase during reaching, and a different temporal pattern of eye-hand coordination. Artificially-induced monocular blur in visually-normal participants did not affect saccades, reaching movements, and eye-hand coordination during a simple reach-to-touch task even after a period of blur exposure. In contrast, patients with anisometropic amblyopia demonstrated significantly different kinematics while performing the same task. These results indicate that loss of visual acuity

  3. Eye-hand coordination in children with high functioning autism and Asperger's disorder using a gap-overlap paradigm.

    PubMed

    Crippa, Alessandro; Forti, Sara; Perego, Paolo; Molteni, Massimo

    2013-04-01

    We investigated eye-hand coordination in children with autism spectrum disorders (ASD) in comparison with age-matched normally developing peers. The eye-hand correlation was measured by putting fixation latencies in relation with pointing and key pressing responses in visual detection tasks where a gap-overlap paradigm was used and compared to fixation latencies in absence of manual response. ASD patients showed less efficient eye-hand coordination, which was particularly evident when pointing towards a target was being fixated. The data of normally developing participants confirmed that manual gap effects are more likely for more complex hand movements. An important discrepancy was discovered in participants with ASD: beside normal eye gap effects, they showed no concurrent hand gap effects when pointing to targets. This result has been interpreted as a further sign of inefficient eye-hand coordination in this patient population.

  4. Effects of hand termination and accuracy constraint on eye-hand coordination during sequential two-segment movements.

    PubMed

    Rand, Miya K; Stelmach, George E

    2010-12-01

    The purpose of this study was to examine the effects of accuracy constraints and termination requirements of hand movement on eye-hand coordination. Healthy adults performed two-segment eye and hand aiming movements to predetermined stationary targets. While two-segment eye movements were made to the first and second targets for all conditions, hand movements were varied across conditions. The first segment had two target sizes to alter accuracy constraints. There were three hand movement types with different termination requirements: (1) stop both at the first and at the second targets, (2) stop at the first target and discontinue, and (3) move through the first target and discontinue. The results showed that the initiation of saccades was moderately correlated with the initiation of hand movements, and both initiations changed in a similar fashion depending on various hand termination requirements. Amplitude of primary saccades and frequency of corrective saccades during the first segment were affected by the combined effects of accuracy constraints and hand termination requirements. These results suggest that the planning and execution of saccades are based in part on global task constraints related to the accuracy and termination demands of hand movements over the two segments. During the transition from the first to the second segment, the gaze was held on the first target until shortly after the pointing to that target was terminated, showing gaze anchoring. The gaze anchoring was prolonged due to the increased accuracy constraint of that target or by including pointing to the second target. However, the gaze anchoring was broken prior to the completion of pointing when the accuracy constraint was reduced and pointing to the second target was excluded. The observed modifications of gaze anchoring imply that the oculomotor system is functionally obligated to fixate a gaze to a pointing target only to the extent that successful completion of a pointing task is

  5. Eye-Hand Coordination in Children with High Functioning Autism and Asperger's Disorder Using a Gap-Overlap Paradigm

    ERIC Educational Resources Information Center

    Crippa, Alessandro; Forti, Sara; Perego, Paolo; Molteni, Massimo

    2013-01-01

    We investigated eye-hand coordination in children with autism spectrum disorders (ASD) in comparison with age-matched normally developing peers. The eye-hand correlation was measured by putting fixation latencies in relation with pointing and key pressing responses in visual detection tasks where a gap-overlap paradigm was used and compared to…

  6. Eye-Hand Coordination in Children with High Functioning Autism and Asperger's Disorder Using a Gap-Overlap Paradigm

    ERIC Educational Resources Information Center

    Crippa, Alessandro; Forti, Sara; Perego, Paolo; Molteni, Massimo

    2013-01-01

    We investigated eye-hand coordination in children with autism spectrum disorders (ASD) in comparison with age-matched normally developing peers. The eye-hand correlation was measured by putting fixation latencies in relation with pointing and key pressing responses in visual detection tasks where a gap-overlap paradigm was used and compared to…

  7. Very Slow Search and Reach: Failure to Maximize Expected Gain in an Eye-Hand Coordination Task

    PubMed Central

    Zhang, Hang; Morvan, Camille; Etezad-Heydari, Louis-Alexandre; Maloney, Laurence T.

    2012-01-01

    We examined an eye-hand coordination task where optimal visual search and hand movement strategies were inter-related. Observers were asked to find and touch a target among five distractors on a touch screen. Their reward for touching the target was reduced by an amount proportional to how long they took to locate and reach to it. Coordinating the eye and the hand appropriately would markedly reduce the search-reach time. Using statistical decision theory we derived the sequence of interrelated eye and hand movements that would maximize expected gain and we predicted how hand movements should change as the eye gathered further information about target location. We recorded human observers' eye movements and hand movements and compared them with the optimal strategy that would have maximized expected gain. We found that most observers failed to adopt the optimal search-reach strategy. We analyze and describe the strategies they did adopt. PMID:23071430

  8. A common control signal and a ballistic stage can explain the control of coordinated eye-hand movements

    PubMed Central

    Gopal, Atul

    2016-01-01

    Voluntary control has been extensively studied in the context of eye and hand movements made in isolation, yet little is known about the nature of control during eye-hand coordination. We probed this with a redirect task. Here subjects had to make reaching/pointing movements accompanied by coordinated eye movements but had to change their plans when the target occasionally changed its position during some trials. Using a race model framework, we found that separate effector-specific mechanisms may be recruited to control eye and hand movements when executed in isolation but when the same effectors are coordinated a unitary mechanism to control coordinated eye-hand movements is employed. Specifically, we found that performance curves were distinct for the eye and hand when these movements were executed in isolation but were comparable when they were executed together. Second, the time to switch motor plans, called the target step reaction time, was different in the eye-alone and hand-alone conditions but was similar in the coordinated condition under assumption of a ballistic stage of ∼40 ms, on average. Interestingly, the existence of this ballistic stage could predict the extent of eye-hand dissociations seen in individual subjects. Finally, when subjects were explicitly instructed to control specifically a single effector (eye or hand), redirecting one effector had a strong effect on the performance of the other effector. Taken together, these results suggest that a common control signal and a ballistic stage are recruited when coordinated eye-hand movement plans require alteration. PMID:26888104

  9. A common control signal and a ballistic stage can explain the control of coordinated eye-hand movements.

    PubMed

    Gopal, Atul; Murthy, Aditya

    2016-06-01

    Voluntary control has been extensively studied in the context of eye and hand movements made in isolation, yet little is known about the nature of control during eye-hand coordination. We probed this with a redirect task. Here subjects had to make reaching/pointing movements accompanied by coordinated eye movements but had to change their plans when the target occasionally changed its position during some trials. Using a race model framework, we found that separate effector-specific mechanisms may be recruited to control eye and hand movements when executed in isolation but when the same effectors are coordinated a unitary mechanism to control coordinated eye-hand movements is employed. Specifically, we found that performance curves were distinct for the eye and hand when these movements were executed in isolation but were comparable when they were executed together. Second, the time to switch motor plans, called the target step reaction time, was different in the eye-alone and hand-alone conditions but was similar in the coordinated condition under assumption of a ballistic stage of ∼40 ms, on average. Interestingly, the existence of this ballistic stage could predict the extent of eye-hand dissociations seen in individual subjects. Finally, when subjects were explicitly instructed to control specifically a single effector (eye or hand), redirecting one effector had a strong effect on the performance of the other effector. Taken together, these results suggest that a common control signal and a ballistic stage are recruited when coordinated eye-hand movement plans require alteration. Copyright © 2016 the American Physiological Society.

  10. Dynamic modulation of illusory and physical target size on separate and coordinated eye and hand movements

    PubMed Central

    Gamble, Christine M.; Song, Joo-Hyun

    2017-01-01

    In everyday behavior, two of the most common visually guided actions—eye and hand movements—can be performed independently, but are often synergistically coupled. In this study, we examine whether the same visual representation is used for different stages of saccades and pointing, namely movement preparation and execution, and whether this usage is consistent between independent and naturalistic coordinated eye and hand movements. To address these questions, we used the Ponzo illusion to dissociate the perceived and physical sizes of visual targets and measured the effects on movement preparation and execution for independent and coordinated saccades and pointing. During independent movements, we demonstrated that both physically and perceptually larger targets produced faster preparation for both effectors. Furthermore, participants who showed a greater influence of the illusion on saccade preparation also showed a greater influence on pointing preparation, suggesting that a shared mechanism involved in preparation across effectors is influenced by illusions. However, only physical but not perceptual target sizes influenced saccade and pointing execution. When pointing was coordinated with saccades, we observed different dynamics: pointing no longer showed modulation from illusory size, while saccades showed illusion modulation for both preparation and execution. Interestingly, in independent and coordinated movements, the illusion modulated saccade preparation more than pointing preparation, with this effect more pronounced during coordination. These results suggest a shared mechanism, dominated by the eyes, may underlie visually guided action preparation across effectors. Furthermore, the influence of illusions on action may operate within such a mechanism, leading to dynamic interactions between action modalities based on task demands. PMID:28362898

  11. The parietal reach region is limb specific and not involved in eye-hand coordination.

    PubMed

    Yttri, Eric A; Wang, Cunguo; Liu, Yuqing; Snyder, Lawrence H

    2014-02-01

    Primates frequently reach toward visual targets. Neurons in early visual areas respond to stimuli in the contralateral visual hemifield and without regard to which limb will be used to reach toward that target. In contrast, neurons in motor areas typically respond when reaches are performed using the contralateral limb and with minimal regard to the visuospatial location of the target. The parietal reach region (PRR) is located early in the visuomotor processing hierarchy. PRR neurons are significantly modulated when targets for either limb or eye movement appear, similar to early sensory areas; however, they respond to targets in either visual field, similar to motor areas. The activity could reflect the subject's attentional locus, movement of a specific effector, or a related function, such as coordinating eye-arm movements. To examine the role of PRR in the visuomotor pathway, we reversibly inactivated PRR. Inactivation effects were specific to contralateral limb movements, leaving ipsilateral limb and saccadic movements intact. Neither visual hemifield bias nor visual attention deficits were observed. Thus our results are consistent with a motoric rather than visual organization in PRR, despite its early location in the visuomotor pathway. We found no effects on the temporal coupling of coordinated saccades and reaches, suggesting that this mechanism lies downstream of PRR. In sum, this study clarifies the role of PRR in the visuomotor hierarchy: despite its early position, it is a limb-specific area influencing reach planning and is positioned upstream from an active eye-hand coordination-coupling mechanism.

  12. Active Collisions in Altered Gravity Reveal Eye-Hand Coordination Strategies

    PubMed Central

    White, Olivier; Lefèvre, Philippe; Wing, Alan M.; Bracewell, R. Martyn; Thonnard, Jean-Louis

    2012-01-01

    Most object manipulation tasks involve a series of actions demarcated by mechanical contact events, and gaze is usually directed to the locations of these events as the task unfolds. Typically, gaze foveates the target 200 ms in advance of the contact. This strategy improves manual accuracy through visual feedback and the use of gaze-related signals to guide the hand/object. Many studies have investigated eye-hand coordination in experimental and natural tasks; most of them highlighted a strong link between eye movements and hand or object kinematics. In this experiment, we analyzed gaze strategies in a collision task but in a very challenging dynamical context. Participants performed collisions while they were exposed to alternating episodes of microgravity, hypergravity and normal gravity. First, by isolating the effects of inertia in microgravity, we found that peak hand acceleration marked the transition between two modes of grip force control. Participants exerted grip forces that paralleled load force profiles, and then increased grip up to a maximum shifted after the collision. Second, we found that the oculomotor strategy adapted visual feedback of the controlled object around the collision, as demonstrated by longer durations of fixation after collision in new gravitational environments. Finally, despite large variability of arm dynamics in altered gravity, we found that saccades were remarkably time-locked to the peak hand acceleration in all conditions. In conclusion, altered gravity allowed light to be shed on predictive mechanisms used by the central nervous system to coordinate gaze, hand and grip motor actions during a mixed task that involved transport of an object and high impact loads. PMID:22984488

  13. Learning robotic eye-arm-hand coordination from human demonstration: a coupled dynamical systems approach.

    PubMed

    Lukic, Luka; Santos-Victor, José; Billard, Aude

    2014-04-01

    We investigate the role of obstacle avoidance in visually guided reaching and grasping movements. We report on a human study in which subjects performed prehensile motion with obstacle avoidance where the position of the obstacle was systematically varied across trials. These experiments suggest that reaching with obstacle avoidance is organized in a sequential manner, where the obstacle acts as an intermediary target. Furthermore, we demonstrate that the notion of workspace travelled by the hand is embedded explicitly in a forward planning scheme, which is actively involved in detecting obstacles on the way when performing reaching. We find that the gaze proactively coordinates the pattern of eye-arm motion during obstacle avoidance. This study provides also a quantitative assessment of the coupling between the eye-arm-hand motion. We show that the coupling follows regular phase dependencies and is unaltered during obstacle avoidance. These observations provide a basis for the design of a computational model. Our controller extends the coupled dynamical systems framework and provides fast and synchronous control of the eyes, the arm and the hand within a single and compact framework, mimicking similar control system found in humans. We validate our model for visuomotor control of a humanoid robot.

  14. Longitudinal patterns of change in eye-hand coordination in children aged 8-16 years.

    PubMed

    Wicks, Lennon J; Telford, Rohan M; Cunningham, Ross B; Semple, Stuart J; Telford, Richard D

    2015-10-01

    Enhanced eye-hand coordination (EHC) is associated with greater participation in physical activity. No longitudinal studies have examined the change in throw-catch EHC from childhood to mid-adolescence. We investigated the development of EHC with an object control test from childhood to mid-adolescence in boys and girls. Evaluated at age 8, 10, 12 and 16 years, EHC was measured as the aggregate success rate of a throw and wall-rebound catch test. The test involved 40 attempts of progressive increasing difficulty, as determined by increased distances from a wall and transitions from two-handed to one-handed catches. Outcomes were treated as quasi-binomial and modelled by generalised linear mixed logistic regression analysis. EHC improved with age from childhood to mid-adolescence, although boys were more adept at each age (p<0.001). The patterns of change in EHC with increasing age varied according to the degree of difficulty of the task (p<0.001); throw and two-handed catch proficiency developing earlier than throw and one-handed catch in both sexes. Boys' EHC was better than girls' as early as age 8 years and male proficiency was maintained through to mid-adolescence. The proficiency of throw and two-handed catch rates developed faster than throw and one-handed catch rates for both sexes.

  15. Saccade-Related Potentials During Eye-Hand Coordination: Effects of Hand Movements on Saccade Preparation.

    PubMed

    Sailer, Uta; Güldenpfennig, Florian; Eggert, Thomas

    2016-07-01

    This study investigated the effect of hand movements on behavioral and electrophysiological parameters of saccade preparation. While event-related potentials were recorded in 17 subjects, they performed saccades to a visual target either together with a hand movement in the same direction, a hand movement in the opposite direction, a hand movement to a third, independent direction, or without any accompanying hand movements. Saccade latencies increased with any kind of accompanying hand movement. Both saccade and manual latencies were largest when both movements aimed at opposite directions. In contrast, saccade-related potentials indicating preparatory activity were mainly affected by hand movements in the same direction. The data suggest that concomitant hand movements interfere with saccade preparation, particularly when the two movements involve motor preparations that access the same visual stimulus. This indicates that saccade preparation is continually informed about hand movement preparation.

  16. Movement order and saccade direction affect a common measure of eye-hand coordination in bimanual reaching

    PubMed Central

    Wang, Cunguo; Ferdoash, Afreen; Snyder, Lawrence H.

    2014-01-01

    Studies of visually guided unimanual reaching have established that a saccade usually precedes each reach and that the reaction times (RTs) for the saccade and reach are highly correlated. The correlation of eye and hand RT is commonly taken as a measure of eye-hand coordination and is thought to assist visuospatial guidance of the hand. We asked what happens during a bimanual reach task. As with a unimanual reach, a saccade was executed first. Although latencies were fastest on unimanual trials, eye and hand RT correlation was identical whether just one or both hands reached to a single target. The average correlation was significantly reduced, however, when each hand reached simultaneously to a different target. We considered three factors that might explain the drop. We found that correlation strength depended on which hand reached first and on which hand reached to the same target as the saccade. Surprisingly, these two factors were largely independent, and the identity of the hand, left or right, had little effect. Eye-hand correlation was similar to that seen with unimanual reaching only when the hand that moved to the same target as the saccade was also the first hand to move. Thus both timing as well as spatial pattern are important in determining eye-hand coordination. PMID:24848462

  17. The Intersection between Ocular and Manual Motor Control: Eye-Hand Coordination in Acquired Brain Injury.

    PubMed

    Rizzo, John-Ross; Hosseini, Maryam; Wong, Eric A; Mackey, Wayne E; Fung, James K; Ahdoot, Edmond; Rucker, Janet C; Raghavan, Preeti; Landy, Michael S; Hudson, Todd E

    2017-01-01

    Acute and chronic disease processes that lead to cerebral injury can often be clinically challenging diagnostically, prognostically, and therapeutically. Neurodegenerative processes are one such elusive diagnostic group, given their often diffuse and indolent nature, creating difficulties in pinpointing specific structural abnormalities that relate to functional limitations. A number of studies in recent years have focused on eye-hand coordination (EHC) in the setting of acquired brain injury (ABI), highlighting the important set of interconnected functions of the eye and hand and their relevance in neurological conditions. These experiments, which have concentrated on focal lesion-based models, have significantly improved our understanding of neurophysiology and underscored the sensitivity of biomarkers in acute and chronic neurological disease processes, especially when such biomarkers are combined synergistically. To better understand EHC and its connection with ABI, there is a need to clarify its definition and to delineate its neuroanatomical and computational underpinnings. Successful EHC relies on the complex feedback- and prediction-mediated relationship between the visual, ocular motor, and manual motor systems and takes advantage of finely orchestrated synergies between these systems in both the spatial and temporal domains. Interactions of this type are representative of functional sensorimotor control, and their disruption constitutes one of the most frequent deficits secondary to brain injury. The present review describes the visually mediated planning and control of eye movements, hand movements, and their coordination, with a particular focus on deficits that occur following neurovascular, neurotraumatic, and neurodegenerative conditions. Following this review, we also discuss potential future research directions, highlighting objective EHC as a sensitive biomarker complement within acute and chronic neurological disease processes.

  18. Freedom and rules in human sequential performance: a refractory period in eye-hand coordination.

    PubMed

    Shalom, Diego E; Sigman, Mariano

    2013-03-11

    In action sequences, the eyes and hands ought to be coordinated in precise ways. The mechanisms governing the architecture of encoding and action of several effectors remain unknown. Here we study hand and eye movements in a sequential task in which letters have to be typed while they move down through the screen. We observe a strict refractory period of about 200 ms between the initiation of manual and eye movements. Subjects do not initiate a saccade just after typing and do not type just after making the saccade. This refractory period is observed ubiquitously in every subject and in each step of the sequential task, even when keystrokes and saccades correspond to different items of the sequence-for instance when a subject types a letter that has been gazed at in a preceding fixation. These results extend classic findings of dual-task paradigms, of a bottleneck tightly locked to the response selection process, to unbounded serial routines. Interestingly, while the bottleneck is seemingly inevitable, better performing subjects can adopt a strategy to minimize the cost of the bottleneck, overlapping the refractory period with the encoding of the next item in the sequence.

  19. Development of an evaluation function for eye-hand coordination robotic therapy.

    PubMed

    Pernalete, N; Tang, F; Chang, S M; Cheng, F Y; Vetter, P; Stegemann, M; Grantner, J

    2011-01-01

    This paper is the continuation of a work presented at ICORR 07, in which we discussed the possibility of improving eye-hand coordination in children diagnosed with this problem, using a robotic mapping from a haptic user interface to a virtual environment. Our goal is to develop, implement and refine a system that will assess and improve the eye-hand coordination and grip strength in children diagnosed with poor graphomotor skills. A detailed analysis of patters (e.g., labyrinths, letters and angles) was conducted in order to select three very distinguishable levels of difficulty that could be included in the system, and which would yield the greatest benefit in terms of assessment of coordination and strength issues as well as in training. Support algorithms (position, force, velocity, inertia and viscosity) were also developed and incorporated into the tasks in order to introduce general computer assistance to the mapping of the user's movements to the computer screen without overriding the user's commands to the robotic device. In order to evaluate performance (given by %accuracy and time) of the executed tasks, a sophisticated evaluation function was designed based on image analysis and edge detection algorithms. This paper presents the development of the haptic tasks, the various assistance algorithms, the description of the evaluation function and the results of a study implemented at the Motor Development Clinic at Cal Poly Pomona. The results (Accuracy and Time) of this function are currently being used as inputs to an Intelligent Decision Support System (described in), which in turn, suggests the next task to be executed by the subject based on his/her performance. © 2011 IEEE

  20. Coordinating one hand with two eyes: optimizing for field of view in a pointing task.

    PubMed

    Khan, Aarlenne Z; Crawford, J Douglas

    2003-02-01

    We previously found that subjects switched 'ocular dominance' as a function of horizontal gaze direction in a reaching task [Vision Res. 41 (14) (2001) 1743]. Here we extend these findings to show that when subjects pointed to targets across the horizontal binocular field, they aligned the fingertip with a vertical plane located between the eyes and the target. This eye-target plane gradually shifted from aligning with the left eye (leftward targets) to between the two eyes (intermediate targets) to the right eye (rightward targets). We suggest that this occurs to optimize eye-hand alignment towards the eye with the best overall field of view.

  1. Eye-hand coordination during reaching. I. Anatomical relationships between parietal and frontal cortex.

    PubMed

    Marconi, B; Genovesio, A; Battaglia-Mayer, A; Ferraina, S; Squatrito, S; Molinari, M; Lacquaniti, F; Caminiti, R

    2001-06-01

    The anatomical and physiological substrata of eye-hand coordination during reaching were studied through combined anatomical and physiological techniques. The association connections of parietal areas V6A and PEc, and those of dorso-rostral (F7) and dorso-caudal (F2) premotor cortex were studied in monkeys, after physiological characterization of the parietal regions where retrograde tracers were injected. The results show that parieto-occipital area V6A is reciprocally connected with F7, and receives a smaller projection from F2. Local parietal projections to V6A arise from areas MIP and, to a lesser extent, 7m, PEa and PEC: On the contrary, parietal area PEc is strongly and reciprocally connected with the part of F2 located close to the pre-central dimple (pre-CD). Local parietal projections to PEc come from a distributed network, including PEa, MIP, PEci and, to a lesser extent, 7m, V6A, 7a and MST. Premotor area F7 receives parietal projections mainly from 7m and V6A, and local frontal projections mainly from F2. On the contrary, premotor area F2 in the pre-CD zone receives parietal inputs from PEc and, to a lesser extent, PEci, while in the peri-arcuate zone F2 receives parietal projections from PEa and MIP. Local frontal projections to F2 pre-CD mostly stem from F4, and, to a lesser extent, from F7 and F3, and CMAd; those addressed to peri-arcuate zone of F2 arise mainly from F5 and, to a lesser extent, from F7, F4, dorsal (CMAd) and ventral (CMAv) cingulate motor areas, pre-supplementary (F6) and supplementary (F3) motor areas. The distribution of association cells in both frontal and parietal cortex was characterized through a spectral analysis that revealed an arrangement of these cells in the form of bands, composed of cell clusters, or 'columns'. The reciprocal connections linking parietal and frontal cortex might explain the presence of visually related and eye-position signals in premotor cortex, as well as the influence of information about arm

  2. Vision and "Hand-Eye" Coordination for the Fujitsu HOAP-2 Humanoid Robot

    NASA Technical Reports Server (NTRS)

    Moore, Jeffrey D.

    2005-01-01

    Software was developed for a Fujitsu HOAP-2 humanoid robot to demonstrate that such "human form" robots can be used to perform useful tasks in an unknown environment; specifically, that they can operate with or in the place of humans to carry out construction operations necessary for space exploration, such as building or maintaining planetary surface habitats for humans. This paper describes the autonomous vision and hand-eye coordination software that enables the HOAP-2 to locate and manipulate objects. Simple vision and pattern detection algorithms including color filtering, noise filtering, image segmentation, orientation filters, and a feedback controlled tracking system enable the robot to locate marked building materials in the workspace. Experimentally determined spatial mappings associate locations in the visual field with the arm joint angles and trajectories necessary to reach these locations, allowing the robot to reach for and manipulate the building materials. These capabilities, when combined with locomotion capabilities, enable the robot to operate autonomously in an unknown workspace.

  3. Vision and "Hand-Eye" Coordination for the Fujitsu HOAP-2 Humanoid Robot

    NASA Technical Reports Server (NTRS)

    Moore, Jeffrey D.

    2005-01-01

    Software was developed for a Fujitsu HOAP-2 humanoid robot to demonstrate that such "human form" robots can be used to perform useful tasks in an unknown environment; specifically, that they can operate with or in the place of humans to carry out construction operations necessary for space exploration, such as building or maintaining planetary surface habitats for humans. This paper describes the autonomous vision and hand-eye coordination software that enables the HOAP-2 to locate and manipulate objects. Simple vision and pattern detection algorithms including color filtering, noise filtering, image segmentation, orientation filters, and a feedback controlled tracking system enable the robot to locate marked building materials in the workspace. Experimentally determined spatial mappings associate locations in the visual field with the arm joint angles and trajectories necessary to reach these locations, allowing the robot to reach for and manipulate the building materials. These capabilities, when combined with locomotion capabilities, enable the robot to operate autonomously in an unknown workspace.

  4. Playing checkers: detection and eye hand coordination in simulated prosthetic vision

    NASA Astrophysics Data System (ADS)

    Dagnelie, Gislin; Walter, Matthias; Yang, Liancheng

    2006-09-01

    In order to assess the potential for visual inspection and eye hand coordination without tactile feedback under conditions that may be available to future retinal prosthesis wearers, we studied the ability of sighted individuals to act upon pixelized visual information at very low resolution, equivalent to 20/2400 visual acuity. Live images from a head-mounted camera were low-pass filtered and presented in a raster of 6 × 10 circular Gaussian dots. Subjects could either freely move their gaze across the raster (free-viewing condition) or the raster position was locked to the subject's gaze by means of video-based pupil tracking (gaze-locked condition). Four normally sighted and one severely visually impaired subject with moderate nystagmus participated in a series of four experiments. Subjects' task was to count 1 to 16 white fields randomly distributed across an otherwise black checkerboard (counting task) or to place a black checker on each of the white fields (placing task). We found that all subjects were capable of learning both tasks after varying amounts of practice, both in the free-viewing and in the gaze-locked conditions. Normally sighted subjects all reached very similar performance levels independent of the condition. The practiced performance level of the visually impaired subject in the free-viewing condition was indistinguishable from that of the normally sighted subjects, but required approximately twice the amount of time to place checkers in the gaze-locked condition; this difference is most likely attributable to this subject's nystagmus. Thus, if early retinal prosthesis wearers can achieve crude form vision, then on the basis of these results they too should be able to perform simple eye hand coordination tasks without tactile feedback.

  5. Eye-Hand Coordination during Visuomotor Adaptation with Different Rotation Angles: Effects of Terminal Visual Feedback

    PubMed Central

    Rand, Miya K.; Rentsch, Sebastian

    2016-01-01

    This study examined adaptive changes of eye-hand coordination during a visuomotor rotation task under the use of terminal visual feedback. Young adults made reaching movements to targets on a digitizer while looking at targets on a monitor where the rotated feedback (a cursor) of hand movements appeared after each movement. Three rotation angles (30°, 75° and 150°) were examined in three groups in order to vary the task difficulty. The results showed that the 30° group gradually reduced direction errors of reaching with practice and adapted well to the visuomotor rotation. The 75° group made large direction errors of reaching, and the 150° group applied a 180° reversal shift from early practice. The 75°and 150° groups, however, overcompensated the respective rotations at the end of practice. Despite these group differences in adaptive changes of reaching, all groups gradually adapted gaze directions prior to reaching from the target area to the areas related to the final positions of reaching during the course of practice. The adaptive changes of both hand and eye movements in all groups mainly reflected adjustments of movement directions based on explicit knowledge of the applied rotation acquired through practice. Only the 30° group showed small implicit adaptation in both effectors. The results suggest that by adapting gaze directions from the target to the final position of reaching based on explicit knowledge of the visuomotor rotation, the oculomotor system supports the limb-motor system to make precise preplanned adjustments of reaching directions during learning of visuomotor rotation under terminal visual feedback. PMID:27812093

  6. Eye-Hand Coordination during Visuomotor Adaptation with Different Rotation Angles: Effects of Terminal Visual Feedback.

    PubMed

    Rand, Miya K; Rentsch, Sebastian

    2016-01-01

    This study examined adaptive changes of eye-hand coordination during a visuomotor rotation task under the use of terminal visual feedback. Young adults made reaching movements to targets on a digitizer while looking at targets on a monitor where the rotated feedback (a cursor) of hand movements appeared after each movement. Three rotation angles (30°, 75° and 150°) were examined in three groups in order to vary the task difficulty. The results showed that the 30° group gradually reduced direction errors of reaching with practice and adapted well to the visuomotor rotation. The 75° group made large direction errors of reaching, and the 150° group applied a 180° reversal shift from early practice. The 75°and 150° groups, however, overcompensated the respective rotations at the end of practice. Despite these group differences in adaptive changes of reaching, all groups gradually adapted gaze directions prior to reaching from the target area to the areas related to the final positions of reaching during the course of practice. The adaptive changes of both hand and eye movements in all groups mainly reflected adjustments of movement directions based on explicit knowledge of the applied rotation acquired through practice. Only the 30° group showed small implicit adaptation in both effectors. The results suggest that by adapting gaze directions from the target to the final position of reaching based on explicit knowledge of the visuomotor rotation, the oculomotor system supports the limb-motor system to make precise preplanned adjustments of reaching directions during learning of visuomotor rotation under terminal visual feedback.

  7. Coordination of Hand Shape

    PubMed Central

    Pesyna, Colin; Pundi, Krishna; Flanders, Martha

    2011-01-01

    The neural control of hand movement involves coordination of the sensory, motor and memory systems. Recent studies have documented the motor coordinates for hand shape, but less is known about the corresponding patterns of somatosensory activity. To initiate this line of investigation, the present study characterized the sense of hand shape by evaluating the influence of differences in the amount of grasping or twisting force, and differences in forearm orientation. Human subjects were asked to use the left hand to report the perceived shape of the right hand. In Experiment 1, six commonly grasped items were arranged on the table in front of the subject: bottle, doorknob, egg, notebook, carton, pan. With eyes closed, subjects used the right hand to lightly touch, forcefully support or imagine holding each object, while 15 joint angles were measured in each hand with a pair of wired gloves. The forces introduced by supporting or twisting did not influence the perceptual report of hand shape, but for most objects, the report was distorted in a consistent manner by differences in forearm orientation. Subjects appeared to adjust the intrinsic joint angles of the left hand, as well as the left wrist posture, so as to maintain the imagined object in its proper spatial orientation. In a second experiment, this result was largely replicated with unfamiliar objects. Thus somatosensory and motor information appear to be coordinated in an object-based, spatial coordinate system, sensitive to orientation relative to gravitational forces, but invariant to grasp forcefulness. PMID:21389230

  8. Benefits of early development of eye-hand coordination: evidence from the LOOK longitudinal study.

    PubMed

    Telford, R D; Cunningham, R B; Telford, R M; Olive, L S; Byrne, D G; Abhayaratna, W P

    2013-10-01

    We investigated longitudinal and cross-sectional relationships between eye-hand coordination (EHC) and cardiorespiratory fitness (multistage run), physical activity (pedometers), percent body fat (%BF, dual energy x-ray absorptiometry), body image, and organized sport participation (questionnaires) in 406 boys and 384 girls at 8 and 10 years of age. EHC was measured by a throw and wall-rebound catch test involving 40 attempts of increasing difficulty. Median EHC improved during two years from 18 to 32 (boys) and 9 to 24 (girls), and gender differences and improvements were both significant (P < 0.001). Cross-sectional analyses showed that boys and girls with better EHC were fitter (P < 0.001), and a longitudinal relationship showed that girls who improved their EHC over the two years became fitter (P < 0.001). There was also evidence that children with better EHC possessed a more positive body image (P = 0.05 for combined sex data), but there was no evidence of any relationships between EHC and %BF or PA (both P > 0.3). Finally, even at age 8 years, boys and girls participating in organized sport possessed better EHC than non-participants. These data provide evidence for the premise that early acquisition of this single motor skill promotes the development of a child's fitness, body image, and participation in sport.

  9. Development of a novel approach to the assessment of eye-hand coordination.

    PubMed

    Lee, Kiseok; Junghans, Barbara M; Ryan, Malcolm; Khuu, Sieu; Suttle, Catherine M

    2014-05-15

    Current methods to measure eye-hand coordination (EHC) have been widely applied in research and practical fields. However, some aspects of the methods, such as subjectivity, high price, portability, and high appraisal contribute to difficulties in EHC testing. The test was developed on an Apple iPad(®) and involves tracing up to 13 shapes with a stylus pen. The time taken to complete each trace and the spatial accuracy of the tracing is automatically recorded. The difficulty level for each shape was evaluated theoretically based on the complexity and length of outline. Ten adults aged 31.5±7.8 years and five children aged 9.4±1.1 years with normal vision participated. In adults, the time taken to trace and number of errors significantly decreased from the first to the second attempt (p<0.05) but not thereafter, suggesting a learning effect with repeatability after a practice attempt. Time taken and number of errors in children were both higher in monocular than binocular viewing conditions (p=0.02 and p<0.01, respectively) while adults' performance was similar in both viewing conditions. Existing EHC tests are subjective in clinics and require higher skills and cost in research, and measure gross EHC. This novel test has been developed to address some of the limitations. The test is engaging for children and adults and is an objective method with potential for the assessment of fine EHC, suited to clinic-based and research use in ophthalmic or brain trauma settings, and in developmental disorders. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Does physical education influence eye-hand coordination? The Lifestyles of our Kids intervention study.

    PubMed

    Wicks, L J; Telford, R M; Cunningham, R B; Semple, S J; Telford, R D

    2016-12-28

    In Australian government-funded primary schools, the responsibility for physical education (PE) falls mainly on general classroom teachers, many of whom possess limited PE training. This study sought to examine the impact of specialist-taught PE on eye-hand coordination (EHC) development. In this 4-year cluster-randomized intervention, participants were 187 boys and 172 girls initially in grade 2 in 29 primary schools, where no school employed university-trained specialist PE teachers. In 13 (intervention) schools, specialist PE teachers conducted 268 PE classes (two 45-minute sessions/wk) from grade 2 to grade 6. The intervention was based on traditional PE educational objectives, including fundamental motor skills, but did not specifically focus on EHC. The remaining 16 (control) schools continued with common-practice PE taught by general classroom teachers (30-60 min/wk). EHC was measured by a ball throw and wall-rebound catch test and recorded at ages 8, 10, and 12 (SD 0.3) at ends of grades 2, 4, and 6, respectively. There was steady yearly improvement of EHC in both groups, but no evidence of any intervention effect in boys (P=.88) or girls (P=.20). The introduction of specialist-taught PE during 4 years of primary school did not influence EHC development. Considering evidence that classroom teachers make little contribution to PE in this jurisdiction, together with the steady progression of EHC over the 4 years, other influences such as organized sport, after-school activities, natural development, and parental instruction are conceivably more influential factors in EHC development during primary school years.

  11. Effects of strabismic amblyopia and strabismus without amblyopia on visuomotor behavior: III. Temporal eye-hand coordination during reaching.

    PubMed

    Niechwiej-Szwedo, Ewa; Goltz, Herbert C; Chandrakumar, Manokaraananthan; Wong, Agnes M F

    2014-11-11

    To examine the effects of strabismic amblyopia and strabismus only, without amblyopia, on the temporal patterns of eye-hand coordination during both the planning and execution stages of visually-guided reaching. Forty-six adults (16 with strabismic amblyopia, 14 with strabismus only, and 16 visually normal) executed reach-to-touch movements toward targets presented randomly 5° or 10° to the left or right of central fixation. Viewing conditions were binocular, monocular viewing with the amblyopic eye, and monocular viewing with the fellow eye (dominant and nondominant viewing for participants without amblyopia). Temporal coordination between eye and hand movements was examined during reach planning (interval between the initiation of saccade and reaching, i.e., saccade-to-reach planning interval) and reach execution (interval between the initiation of saccade and reach peak velocity [PV], i.e., saccade-to-reach PV interval). The frequency and dynamics of secondary reach-related saccades were also examined. The temporal patterns of eye-hand coordination prior to reach initiation were comparable among participants with strabismic amblyopia, strabismus only, and visually normal adults. However, the reach acceleration phase of participants with strabismic amblyopia and those with strabismus only were longer following target fixation (saccade-to-reach PV interval) than that of visually normal participants (P < 0.05). This effect was evident under all viewing conditions. The saccade-to-reach planning interval and the saccade-to-reach PV interval were not significantly different among participants with amblyopia with different levels of acuity and stereo acuity loss. Participants with strabismic amblyopia and strabismus only initiated secondary reach-related saccades significantly more frequently than visually normal participants. The amplitude and peak velocity of these saccades were significantly greater during amblyopic eye viewing in participants with amblyopia who

  12. Preparing coordinated eye and hand movements: dual-task costs are not attentional.

    PubMed

    Jonikaitis, Donatas; Schubert, Torsten; Deubel, Heiner

    2010-12-20

    Dual-task costs are observed when people perform two tasks at the same time. It has been suggested that these costs arise from limitations of movement goal selection when multiple goal-directed movements are made simultaneously. To investigate this, we asked participants to reach and look at different locations while we varied the time between the cues to start the eye and the hand movement between 150 ms and 900 ms. In Experiment 1, participants executed the reach first, and the saccade second, in Experiment 2 the order of the movements was reversed. We observed dual-task costs-participants were slower to start the eye or hand movement if they were planning another movement at that time. In Experiment 3, we investigated whether these dual-task costs were due to limited attentional resources needed to select saccade and reach goal locations. We found that the discrimination of a probe improved at both saccade and reach locations, indicating that attention shifted to both movement goals. Importantly, while we again observed the expected dual-task costs as reflected in movement latencies, there was no apparent delay of the associated attention shifts. Our results rule out attentional goal selection as the causal factor leading to the dual-task costs occurring in eye-hand movements.

  13. [The psychomotor test for research of eye-hand coordination at performance of monotonous activity on tracking target].

    PubMed

    Dorokhov, V B; Arsen'ev, G N; Tkachenko, O N; Zakharchenko, D V; Lavrova, T P; Dementienko, V V

    2011-01-01

    Visual-motor coordination is necessary for successful performance of everyday activities. Many tasks, such as driving or operating devices in the workplace, require a variety of coordination patterns with different levels of compatibility between the eyes and the hand. The psychomotor test was developed which makes it possible to analyze visual-motor coordination disorders caused by a decrease in the level of wakefulness. A small circular target (14 mm in diameter) was moving with a low constant velosity (12 mm/s) in a circular trajectory (80 mm in diameter) with a period of 20 s. Subjects were instructed to keep the mouse-driven cursor inside a target, overstepping the limits of the moving target was considered as an error. To test the attention level, an additional stimulus was introduced which appeared for 3 seconds with an interval of 15 to 40 s. When the stimulus appeared, it was required to touch it with the cursor and click the mouse button. Cursor trajectories have a temporal resolution of 120 Hz. Eye movements were recorded with a PC-based Eyegaze Development System (LC Technologies, USA) measuring corneal reflectance with a collection rate of 120 Hz. Monotonous character of the test performance induced drowsiness and led to errors 25-30 minutes after the beginning of the experiment. Changes in physiological vigilance level was evaluated with EEG recording. Analysis of the dynamic characteristics of smooth and saccadic eye movements and hand movements showed their high sensitivity to a decrease in efficiency of operator's activity caused by a drop in the level of wakefulness. It is suggested that further development of this approach to measuring eye-hand coordination will promote working out a contactless method for the express diagnostics of the critical levels of drowsiness as well as for the definition of professional characteristics of an operator.

  14. The Relationship of Level of Eye-Hand Coordination and Answer Marking Format to the Test Performance of First- and Second- Grade Pupils; Implications For Test Validity.

    ERIC Educational Resources Information Center

    Ramseyer, Gary C.; Cashen, Valjean M.

    1985-01-01

    The study explored the relationship of eye-hand coordination differentiated by three levels and two answer marking formats (test booklet and answer sheet). Simple effects tests indicated significant differences in favor of the booklet format for low and middle range eye-hand groups but not for the high group. (DWH)

  15. The Relationship of Level of Eye-Hand Coordination and Answer Marking Format to the Test Performance of First- and Second- Grade Pupils; Implications For Test Validity.

    ERIC Educational Resources Information Center

    Ramseyer, Gary C.; Cashen, Valjean M.

    1985-01-01

    The study explored the relationship of eye-hand coordination differentiated by three levels and two answer marking formats (test booklet and answer sheet). Simple effects tests indicated significant differences in favor of the booklet format for low and middle range eye-hand groups but not for the high group. (DWH)

  16. Development of a global motor rating scale for young children (0-4 years) including eye-hand grip coordination.

    PubMed

    Vaivre-Douret, L; Burnod, Y

    2001-11-01

    A comparative study of the eight motor rating scales available in Western countries demonstrated methodological differences in the choice of items and standardization. We have developed a global motor rating scale that includes items which measure postural-motor, locomotor (PML) and eye-hand grip coordination (EHGC), and which allows the assessment of an average of motor function level (MFL), PML and EHGC development. Scores obtained were used to define the acquisition of motor age based on the skills completed. The items were selected on the basis of the average age at which the function developed in two populations of healthy full-term French infants, followed from birth to 4 months (n = 60) and from 4 months to 4 years (n = 63). Recent French developmental standards (mean age and standard deviation) of acquisition allow the identification of neuro-psychomotor deviations from normal motor behaviour. This includes both static and dynamic motor coordination sequences. Inter-examiner correlations (n = 3) for 15 randomly selected children indicated a coefficient of 0.90. The scale revealed a sequence in the organization of learned postural-motor, locomotor and eye-hand gripping skills which can contribute to the understanding of brain areas implicated in this maturation process.

  17. Age- and stereovision-dependent eye-hand coordination deficits in children with amblyopia and abnormal binocularity.

    PubMed

    Grant, Simon; Suttle, Catherine; Melmoth, Dean R; Conway, Miriam L; Sloper, John J

    2014-08-05

    To examine factors contributing to eye-hand coordination deficits in children with amblyopia and impaired stereovision. Participants were 55 anisometropic or strabismic children aged 5.0 to 9.25 years with different degrees of amblyopia and abnormal binocularity, along with 28 age-matched visually-normal controls. Pilot data were obtained from four additional patients studied longitudinally at different treatment stages. Movements of the preferred hand were recorded using a 3D motion-capture system while subjects reached-to-precision grasp objects (two sizes, three locations) under binocular, dominant eye, and amblyopic/nonsighting eye conditions. Kinematic and "error" performance measures were quantified and compared by viewing condition and subject group using ANOVA, stepwise regression, and correlation analyses. Movements of the younger amblyopes (age 5-6 years; n = 30) were much slower, particularly in the final approach to the objects, and contained more spatial errors in reaching (∼×1.25-1.75) and grasping (∼×1.75-2.25) under all three views (P < 0.05) than their age-matched controls (n = 13). Amblyopia severity was the main contributor to their slower movements with absent stereovision a secondary factor and the unique determinant of their increased error-rates. Older amblyopes (age 7-9 years; n = 25) spent longer contacting the objects before lifting them (P = 0.015) compared with their matched controls (n = 15), with absence of stereovision still solely related to increases in reach and grasp errors, although these occurred less frequently than in younger patients. Pilot prospective data supported these findings by showing positive treatment-related associations between improved stereovision and reach-to-grasp performance. Strategies that children with amblyopia and abnormal binocularity use for reach-to-precision grasping change with age, from emphasis on visual feedback during the "in-flight" approach at ages 5 to 6 years to more reliance on

  18. Development of a model of machine hand eye coordination and program specifications for a topological machine vision system

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A unified approach to computer vision and manipulation is developed which is called choreographic vision. In the model, objects to be viewed by a projected robot in the Viking missions to Mars are seen as objects to be manipulated within choreographic contexts controlled by a multimoded remote, supervisory control system on Earth. A new theory of context relations is introduced as a basis for choreographic programming languages. A topological vision model is developed for recognizing objects by shape and contour. This model is integrated with a projected vision system consisting of a multiaperture image dissector TV camera and a ranging laser system. System program specifications integrate eye-hand coordination and topological vision functions and an aerospace multiprocessor implementation is described.

  19. Determining eye-hand coordination using the sport vision trainer: an evaluation of test-retest reliability.

    PubMed

    Ellison, Paul H; Sparks, S Andy; Murphy, Philip N; Carnegie, Evelyn; Marchant, David C

    2014-01-01

    The purpose of this investigation was to assess the number of test-retest trials required to familiarize participants in order to provide acceptable reliability for the measurement of an eye-hand coordination task using the Sport Vision Trainer (SVT). Two schedules were conducted (S1 and S2). For S1, 64 participants (male n = 51, age 20.8 ± 4.9 years; female n = 13, age 20.1 ± 2.1 years) attended four sessions each 1 week apart, and undertook four trials using the SVT. For S2, 60 participants (male n = 46, age 20.8 ± 4.9 years; female n = 14, age 20.1 ± 2.1 years) attended one 20-minute schedule consisting of four consecutive trials using the SVT. Limits of agreement (LoA) analyses showed that absolute reliability was increased in both studies. The LoA for S2 indicate that error decreased between trial 1-2, 2-3, and 3-4; ± 0.95 (CI, -1.16, +2.56sec), ± 0.97 (CI, -1.66, +2.14sec), ± 0.69 (CI, -1.08, +1.62sec). It was concluded that reliable measurements of eye-hand coordination can be obtained using the SVT in one session.

  20. Adaptive Responses in Eye-Head-Hand Coordination Following Exposures to a Virtual Environment as a Possible Space Flight Analog

    NASA Technical Reports Server (NTRS)

    Harm, Deborah L.; Taylor, L. C.; Bloomberg, J. J.

    2007-01-01

    Virtual environments (VE) offer unique training opportunities, particularly for training astronauts and preadapting them to the novel sensory conditions of microgravity. Sensorimotor aftereffects of VEs are often quite similar to adaptive sensorimotor responses observed in astronauts during and/or following space flight. The purpose of this research was to compare disturbances in sensorimotor coordination produced by dome virtual environment display and to examine the effects of exposure duration, and repeated exposures to VR systems. The current study examined disturbances in eye-head-hand (EHH) and eye-head coordination. Preliminary results will be presented. Eleven subjects have participated in the study to date. One training session was completed in order to achieve stable performance on the EHH coordination and VE tasks. Three experimental sessions were performed each separated by one day. Subjects performed a navigation and pick and place task in a dome immersive display VE for 30 or 60 min. The subjects were asked to move objects from one set of 15 pedestals to the other set across a virtual square room through a random pathway as quickly and accurately as possible. EHH coordination was measured before, immediately after, and at 1 hr, 2 hr, 4 hr and 6 hr following exposure to VR. EHH coordination was measured as position errors and reaction time in a pointing task that included multiple horizontal and vertical LED targets. Repeated measures ANOVAs were used to analyze the data. In general, we observed significant increases in position errors for both horizontal and vertical targets. The largest decrements were observed immediately following exposure to VR and showed a fairly rapid recovery across test sessions, but not across days. Subjects generally showed faster RTs across days. Individuals recovered from the detrimental effects of exposure to the VE on position errors within 1-2 hours. The fact that subjects did not significantly improve across days

  1. Adaptive Responses in Eye-Head-Hand Coordination Following Exposures to a Virtual Environment as a Possible Space Flight Analog

    NASA Technical Reports Server (NTRS)

    Harm, Deborah L.; Taylor, L. C.; Bloomberg, J. J.

    2007-01-01

    Virtual environments (VE) offer unique training opportunities, particularly for training astronauts and preadapting them to the novel sensory conditions of microgravity. Sensorimotor aftereffects of VEs are often quite similar to adaptive sensorimotor responses observed in astronauts during and/or following space flight. The purpose of this research was to compare disturbances in sensorimotor coordination produced by dome virtual environment display and to examine the effects of exposure duration, and repeated exposures to VR systems. The current study examined disturbances in eye-head-hand (EHH) and eye-head coordination. Preliminary results will be presented. Eleven subjects have participated in the study to date. One training session was completed in order to achieve stable performance on the EHH coordination and VE tasks. Three experimental sessions were performed each separated by one day. Subjects performed a navigation and pick and place task in a dome immersive display VE for 30 or 60 min. The subjects were asked to move objects from one set of 15 pedestals to the other set across a virtual square room through a random pathway as quickly and accurately as possible. EHH coordination was measured before, immediately after, and at 1 hr, 2 hr, 4 hr and 6 hr following exposure to VR. EHH coordination was measured as position errors and reaction time in a pointing task that included multiple horizontal and vertical LED targets. Repeated measures ANOVAs were used to analyze the data. In general, we observed significant increases in position errors for both horizontal and vertical targets. The largest decrements were observed immediately following exposure to VR and showed a fairly rapid recovery across test sessions, but not across days. Subjects generally showed faster RTs across days. Individuals recovered from the detrimental effects of exposure to the VE on position errors within 1-2 hours. The fact that subjects did not significantly improve across days

  2. The effect of methylphenidate and placebo on eye-hand coordination functioning and handwriting of children with attention deficit hyperactivity disorder.

    PubMed

    Lufi, Dubi; Gai, Elisheva

    2007-10-01

    Israeli children who were diagnosed as having attention deficit hyperactivity disorder participated in the study. The children were assessed three times in a specially constructed battery of tests. The battery of tests included variables assessing eye-hand coordination skills, writing, and behavioral assessment of the teacher. The design was in the format of a double blind, randomized, crossover, placebo-control procedure. The results showed that methylphenidate (MPH) improved some cognitive functions of eye-hand coordination slightly better than placebo. In addition, behavior variables assessed by the teachers improved only under the influence of MPH.

  3. Inter- and intrasensory modality matching in children with hand-eye coordination problems: exploring the developmental lag hypothesis.

    PubMed

    Sigmundsson, H; Ingvaldsen, R P; Whiting, H T

    1997-12-01

    This study set out to explore the suggestion that the problems experienced by 8-year-old children diagnosed as clumsy in the area of hand-eye coordination (HECP) might be attributed to a developmental lag. The performances of this group of HECP children were compared with those of groups of 5-year-old and 8-year-old controls without such deficits, when required to carry out a task involving pointing, without vision, to targets located, visually, visually/proprioceptively, or proprioceptively, the dependent variable being the distance error score from the centre of the target. The performances of the HECP children, when vision or vision/proprioception was used to locate the targets, were shown to be inferior to those of the two control groups of children thereby supporting a visual deficit hypothesis. When the targets had to be located proprioceptively, the performance of the HECP children was shown to be similar to that of the 5-year-olds, while both groups were inferior to the 8-year-olds, thereby supporting a developmental lag hypothesis in proprioceptive terms. However, when the scores for the preferred and non-preferred hands were analysed separately a marked deterioration in the performances of both the 5-year-old controls and the HECP children was observed while the 8-year-old controls were unaffected. While this finding supports a developmental lag explanation of the inferior performances of the HECP children, it was necessary to qualify such an explanation when the within-group performances using the preferred and non-preferred hands were compared. Only the HECP children, under the visual/proprioceptive or proprioceptive conditions, showed significant performance differences, in favour of the preferred hand. This finding was taken as a suggestion that the developmental lag exhibited by the HECP children might have pathological overtones possibly related to the development of the corpus callosum.

  4. Hand-Eye Calibration Using Active Vision

    NASA Technical Reports Server (NTRS)

    Nickels, Kevin; Huber, Eric; DiCicco, Matthew

    2007-01-01

    The project described in this paper designed and implemented a hand-eye calibration method for manipulators under observation by stereo cameras. This method has been utilized on Johnson Space Center's Robonaut, and on a planetary manipulator mock-up at the Jet Propulsion Laboratory. The intent of this calibration is to improve the manipulator's hand-eye coordination.

  5. The effects of auditorally augmented feedback on the eye-hand coordination of students with cerebral palsy.

    PubMed

    Talbot, M L; Junkala, J

    1981-08-01

    To explore the question of whether auditorally augmented feedback can improve the eye-hand coordination of individuals with cerebral palsy, 59 (cerebral-palsied) students (mean chronological age 14 years, 3 months) were pretested with the Southern California Motor Accuracy Test and then randomly assigned to three groups. Group 1 performed training exercises-tracing line drawings-while simultaneously receiving auditorally augmented feedback about their efforts. Group 2 performed the same training exercises without the augmented feedback. Group 3 served as controls. All subjects were post-tested with the Southern California Motor Accuracy Test, followed by a second post-test after a 3-month interval. At the first post-test, the performance of the feedback group was significantly superior to that of the other groups. At the second post-test, the performance patterns among the groups were essentially the same as the time of the first post-test, but between-group differences were no longer significant. The results of this study are discussed in both empirical and theoretical terms.

  6. THE COLLECTION AND STATISTICAL EVALUATION OF QUANTITATIVE DATA FOR HAND-EYE COORDINATION WITH RESPECT TO DETERMINING ITS CORRELATION WITH READING DISABILITY AT BOTH THE PRIMARY AND SECONDARY SCHOOL LEVELS. FINAL REPORT.

    ERIC Educational Resources Information Center

    KEAR, EDWARD; MACLEAN, GEORGE

    THE POSSIBILITY OF A CORRELATION BETWEEN HAND-EYE COORDINATION AND READING DISABILITY WAS INVESTIGATED. CHILDREN FROM GRADES 2 TO 12 WERE TESTED TO DETERMINE THEIR HAND-EYE COORDINATION USING A PORTABLE TESTING DEVICE FOR QUANTATIVE MEASURE RECENTLY DEVELOPED. THE SUBJECTS INCLUDED APPROXIMATELY 1,700 NORMAL PUBLIC SCHOOL STUDENTS AND 290 STUDENTS…

  7. Effects of conventional neurological treatment and a virtual reality training program on eye-hand coordination in children with cerebral palsy.

    PubMed

    Shin, Ji-Won; Song, Gui-Bin; Hwangbo, Gak

    2015-07-01

    [Purpose] The purpose of the study was to evaluate the effects of conventional neurological treatment and a virtual reality training program on eye-hand coordination in children with cerebral palsy. [Subjects] Sixteen children (9 males, 7 females) with spastic diplegic cerebral palsy were recruited and randomly assigned to the conventional neurological physical therapy group (CG) and virtual reality training group (VRG). [Methods] Eight children in the control group performed 45 minutes of therapeutic exercise twice a week for eight weeks. In the experimental group, the other eight children performed 30 minutes of therapeutic exercise and 15 minutes of a training program using virtual reality twice a week during the experimental period. [Results] After eight weeks of the training program, there were significant differences in eye-hand coordination and visual motor speed in the comparison of the virtual reality training group with the conventional neurological physical therapy group. [Conclusion] We conclude that a well-designed training program using virtual reality can improve eye-hand coordination in children with cerebral palsy.

  8. Does an eye-hand coordination test have added value as part of talent identification in table tennis? A validity and reproducibility study.

    PubMed

    Faber, Irene R; Oosterveld, Frits G J; Nijhuis-Van der Sanden, Maria W G

    2014-01-01

    This study investigated the added value, i.e. discriminative and concurrent validity and reproducibility, of an eye-hand coordination test relevant to table tennis as part of talent identification. Forty-three table tennis players (7-12 years) from national (n = 13), regional (n = 11) and local training centres (n = 19) participated. During the eye-hand coordination test, children needed to throw a ball against a vertical positioned table tennis table with one hand and to catch the ball correctly with the other hand as frequently as possible in 30 seconds. Four different test versions were assessed varying the distance to the table (1 or 2 meter) and using a tennis or table tennis ball. 'Within session' reproducibility was estimated for the two attempts of the initial tests and ten youngsters were retested after 4 weeks to estimate 'between sessions' reproducibility. Validity analyses using age as covariate showed that players from the national and regional centres scored significantly higher than players from the local centre in all test versions (p<0.05). The tests at 1 meter demonstrated better discriminative ability than those at 2 meter. While all tests but one had a positive significant association with competition outcome, which were corrected for age influences, the version with a table tennis ball at 1 meter showed the highest association (r = 0.54; p = 0.001). Differences between the first and second attempts were comparable for all test versions (between -8 and +7 repetitions) with ICC's ranging from 0.72 to 0.87. The smallest differences were found for the test with a table tennis ball at 1 meter (between -3 and +3 repetitions). Best test version as part of talent identification appears to be the version with a table tennis ball at 1 meter regarding the psychometric characteristics evaluated. Longitudinal studies are necessary to evaluate the predictive value of this test.

  9. Teaching skills to use a computer mouse in preschoolers with developmental disabilities: shaping moving a mouse and eye-hand coordination.

    PubMed

    Shimizu, Hirofumi; Yoon, Soyoung; McDonough, Christopher S

    2010-01-01

    We taught seven preschoolers with developmental disabilities to point-and-click with a computer mouse. The computer-based training program consisted of three parts, based on a task analysis of the behavioral prerequisites to point-and-click. Training 1 was designed to shape moving the mouse. Training 2 was designed to build eye-hand coordination by teaching the children to move the on-screen cursor onto specific items on the screen. Training 3 was designed to teach pressing and releasing the mouse button. An instructor provided prompts and blocking to facilitate skill acquisition. A multiple baseline design across participants was used to evaluate the effectiveness of the training program. The results showed that all participants learned to point-and-click after exposure to the training program.

  10. Does an Eye-Hand Coordination Test Have Added Value as Part of Talent Identification in Table Tennis? A Validity and Reproducibility Study

    PubMed Central

    Faber, Irene R.; Oosterveld, Frits G. J.; Nijhuis-Van der Sanden, Maria W. G.

    2014-01-01

    This study investigated the added value, i.e. discriminative and concurrent validity and reproducibility, of an eye-hand coordination test relevant to table tennis as part of talent identification. Forty-three table tennis players (7–12 years) from national (n = 13), regional (n = 11) and local training centres (n = 19) participated. During the eye-hand coordination test, children needed to throw a ball against a vertical positioned table tennis table with one hand and to catch the ball correctly with the other hand as frequently as possible in 30 seconds. Four different test versions were assessed varying the distance to the table (1 or 2 meter) and using a tennis or table tennis ball. ‘Within session’ reproducibility was estimated for the two attempts of the initial tests and ten youngsters were retested after 4 weeks to estimate ‘between sessions’ reproducibility. Validity analyses using age as covariate showed that players from the national and regional centres scored significantly higher than players from the local centre in all test versions (p<0.05). The tests at 1 meter demonstrated better discriminative ability than those at 2 meter. While all tests but one had a positive significant association with competition outcome, which were corrected for age influences, the version with a table tennis ball at 1 meter showed the highest association (r = 0.54; p = 0.001). Differences between the first and second attempts were comparable for all test versions (between −8 and +7 repetitions) with ICC's ranging from 0.72 to 0.87. The smallest differences were found for the test with a table tennis ball at 1 meter (between −3 and +3 repetitions). Best test version as part of talent identification appears to be the version with a table tennis ball at 1 meter regarding the psychometric characteristics evaluated. Longitudinal studies are necessary to evaluate the predictive value of this test. PMID:24465638

  11. Unconstrained reaching modulates eye-hand coupling

    PubMed Central

    Lee, Dongpyo; Poizner, Howard; Corcos, Daniel M.; Henriques, Denise Y.

    2013-01-01

    Eye-hand coordination is a crucial element of goal-directed movements. However, few studies have looked at the extent to which unconstrained movements of the eyes and hand made to targets influence each other. We studied human participants who moved either their eyes, or both their eyes and hand to one of three static or flashed targets presented in 3D space. The eyes were directed and hand located at a common start position on either the right or left side of the body. We found that the velocity and scatter of memory-guided saccades (flashed targets) differed significantly when produced in combination with a reaching movement than when produced alone. Specifically, when accompanied by a reach, peak saccadic velocities were lower than when the eye moved alone. Peak saccade velocities, as well as latencies, were also highly correlated with those for reaching movements, especially for the briefly flashed targets compared to the continuous visible target. The scatter of saccade endpoints was greater when the saccades were produced with the reaching movement than when produced without, and the size of the scatter for both saccades and reaches were weakly correlated. These findings suggest that the saccades and reaches made to 3D targets are weakly to moderately coupled both temporally and spatially, and that this is partly the result of the arm movement influencing the eye movement. Taken together this study provides further evidence that the oculomotor and arm motor systems interact above and beyond any common target representations shared by the two motor systems. PMID:24121521

  12. Eye-Hand Co-Ordination and Handedness': A Developmental Study of Visuo-Motor Behaviour in Infancy

    ERIC Educational Resources Information Center

    Seth, G.

    1973-01-01

    Consistently over the three test situations, initial left-handedness' gives way during the third quarter of the first year to right-hand dominance. The way in which the shift occurs lends support to a maturational, rather than a learning or social pressure explanation of lateral asymmetry. (Author/CB)

  13. Eye-Hand Co-Ordination and Handedness': A Developmental Study of Visuo-Motor Behaviour in Infancy

    ERIC Educational Resources Information Center

    Seth, G.

    1973-01-01

    Consistently over the three test situations, initial left-handedness' gives way during the third quarter of the first year to right-hand dominance. The way in which the shift occurs lends support to a maturational, rather than a learning or social pressure explanation of lateral asymmetry. (Author/CB)

  14. Effects of Ving Tsun Chinese Martial Art Training on Upper Extremity Muscle Strength and Eye-Hand Coordination in Community-Dwelling Middle-Aged and Older Adults: A Pilot Study

    PubMed Central

    Ng, Shamay S. M.; Cheng, Yoyo T. Y.; Yu, Esther Y. T.; Chow, Gary C. C.; Chak, Yvonne T. C.; Chan, Ivy K. Y.; Zhang, Joni; Macfarlane, Duncan

    2016-01-01

    Objectives. To evaluate the effects of Ving Tsun (VT) martial art training on the upper extremity muscle strength and eye-hand coordination of middle-aged and older adults. Methods. This study used a nonequivalent pretest-posttest control group design. Forty-two community-dwelling healthy adults participated in the study; 24 (mean age ± SD = 68.5 ± 6.7 years) underwent VT training for 4 weeks (a supervised VT session twice a week, plus daily home practice), and 18 (mean age ± SD = 72.0 ± 6.7 years) received no VT training and acted as controls. Shoulder and elbow isometric muscle strength and eye-hand coordination were evaluated using the Lafayette Manual Muscle Test System and a computerized finger-pointing test, respectively. Results. Elbow extensor peak force increased by 13.9% (P = 0.007) in the VT group and the time to reach peak force decreased (9.9%) differentially in the VT group compared to the control group (P = 0.033). For the eye-hand coordination assessment outcomes, reaction time increased by 2.9% in the VT group and decreased by 5.3% in the control group (P = 0.002). Conclusions. Four weeks of VT training could improve elbow extensor isometric peak force and the time to reach peak force but not eye-hand coordination in community-dwelling middle-aged and older adults. PMID:27525020

  15. Effects of Ving Tsun Chinese Martial Art Training on Upper Extremity Muscle Strength and Eye-Hand Coordination in Community-Dwelling Middle-Aged and Older Adults: A Pilot Study.

    PubMed

    Fong, Shirley S M; Ng, Shamay S M; Cheng, Yoyo T Y; Wong, Janet Y H; Yu, Esther Y T; Chow, Gary C C; Chak, Yvonne T C; Chan, Ivy K Y; Zhang, Joni; Macfarlane, Duncan; Chung, Louisa M Y

    2016-01-01

    Objectives. To evaluate the effects of Ving Tsun (VT) martial art training on the upper extremity muscle strength and eye-hand coordination of middle-aged and older adults. Methods. This study used a nonequivalent pretest-posttest control group design. Forty-two community-dwelling healthy adults participated in the study; 24 (mean age ± SD = 68.5 ± 6.7 years) underwent VT training for 4 weeks (a supervised VT session twice a week, plus daily home practice), and 18 (mean age ± SD = 72.0 ± 6.7 years) received no VT training and acted as controls. Shoulder and elbow isometric muscle strength and eye-hand coordination were evaluated using the Lafayette Manual Muscle Test System and a computerized finger-pointing test, respectively. Results. Elbow extensor peak force increased by 13.9% (P = 0.007) in the VT group and the time to reach peak force decreased (9.9%) differentially in the VT group compared to the control group (P = 0.033). For the eye-hand coordination assessment outcomes, reaction time increased by 2.9% in the VT group and decreased by 5.3% in the control group (P = 0.002). Conclusions. Four weeks of VT training could improve elbow extensor isometric peak force and the time to reach peak force but not eye-hand coordination in community-dwelling middle-aged and older adults.

  16. Teaching Skills to Use a Computer Mouse in Preschoolers with Developmental Disabilities: Shaping Moving a Mouse and Eye-Hand Coordination

    ERIC Educational Resources Information Center

    Shimizu, Hirofumi; Yoon, Soyoung; McDonough, Christopher S.

    2010-01-01

    We taught seven preschoolers with developmental disabilities to point-and-click with a computer mouse. The computer-based training program consisted of three parts, based on a task analysis of the behavioral prerequisites to point-and-click. Training 1 was designed to shape moving the mouse. Training 2 was designed to build eye-hand coordination…

  17. Teaching Skills to Use a Computer Mouse in Preschoolers with Developmental Disabilities: Shaping Moving a Mouse and Eye-Hand Coordination

    ERIC Educational Resources Information Center

    Shimizu, Hirofumi; Yoon, Soyoung; McDonough, Christopher S.

    2010-01-01

    We taught seven preschoolers with developmental disabilities to point-and-click with a computer mouse. The computer-based training program consisted of three parts, based on a task analysis of the behavioral prerequisites to point-and-click. Training 1 was designed to shape moving the mouse. Training 2 was designed to build eye-hand coordination…

  18. Hand-Eye Calibration of Robonaut

    NASA Technical Reports Server (NTRS)

    Nickels, Kevin; Huber, Eric

    2004-01-01

    NASA's Human Space Flight program depends heavily on Extra-Vehicular Activities (EVA's) performed by human astronauts. EVA is a high risk environment that requires extensive training and ground support. In collaboration with the Defense Advanced Research Projects Agency (DARPA), NASA is conducting a ground development project to produce a robotic astronaut's assistant, called Robonaut, that could help reduce human EVA time and workload. The project described in this paper designed and implemented a hand-eye calibration scheme for Robonaut, Unit A. The intent of this calibration scheme is to improve hand-eye coordination of the robot. The basic approach is to use kinematic and stereo vision measurements, namely the joint angles self-reported by the right arm and 3-D positions of a calibration fixture as measured by vision, to estimate the transformation from Robonaut's base coordinate system to its hand coordinate system and to its vision coordinate system. Two methods of gathering data sets have been developed, along with software to support each. In the first, the system observes the robotic arm and neck angles as the robot is operated under external control, and measures the 3-D position of a calibration fixture using Robonaut's stereo cameras, and logs these data. In the second, the system drives the arm and neck through a set of pre-recorded configurations, and data are again logged. Two variants of the calibration scheme have been developed. The full calibration scheme is a batch procedure that estimates all relevant kinematic parameters of the arm and neck of the robot The daily calibration scheme estimates only joint offsets for each rotational joint on the arm and neck, which are assumed to change from day to day. The schemes have been designed to be automatic and easy to use so that the robot can be fully recalibrated when needed such as after repair, upgrade, etc, and can be partially recalibrated after each power cycle. The scheme has been implemented on

  19. Hand-eye calibration using dual quaternions in medical environment

    NASA Astrophysics Data System (ADS)

    Briese, Danilo; Niebler, Christine; Rose, Georg

    2014-03-01

    Nowadays medical interventions are often supported by localization systems using different measurement tools (MT). This requires to register the MT coordinate sytem to the world coordinate system used by the medical device. The hand-eye calibration is a well-known method from robotics to estimate the transformation between the gripper of a robot (hand) and a MT (eye) rigidly attached to the robot. Using a calibration tool (e.g. checker board) one can obtain the hand-eye transformation using known relative movements of the robot and the data from the MT. The approach can also be used for MT located elsewhere * using markers on the device. The position of the markers is not required to be known since they are rigid during the motions. Based on prior work using dual quaternions to represent transformations in the SE(3) we not only took into account movements between immediate neighbour positions Pi and Pj , but combined all positions to gain (P/2) submotions in every subset Σ p/n=3 (p/n) t without increasing the number of positions conducted during the calibration. We took into account the unity constraint for dual quaternions since only those represent rigid motions in space. We performed simulations that show the advantage of our algorithm. Additionally we gained experimental data which supported the outcome of the simulations. We can outline that our approach achieves more accurate results estimating the hand-eye transformation than the aforementioned algorithms.

  20. A computationally efficient method for hand-eye calibration.

    PubMed

    Zhang, Zhiqiang; Zhang, Lin; Yang, Guang-Zhong

    2017-07-19

    Surgical robots with cooperative control and semiautonomous features have shown increasing clinical potential, particularly for repetitive tasks under imaging and vision guidance. Effective performance of an autonomous task requires accurate hand-eye calibration so that the transformation between the robot coordinate frame and the camera coordinates is well defined. In practice, due to changes in surgical instruments, online hand-eye calibration must be performed regularly. In order to ensure seamless execution of the surgical procedure without affecting the normal surgical workflow, it is important to derive fast and efficient hand-eye calibration methods. We present a computationally efficient iterative method for hand-eye calibration. In this method, dual quaternion is introduced to represent the rigid transformation, and a two-step iterative method is proposed to recover the real and dual parts of the dual quaternion simultaneously, and thus the estimation of rotation and translation of the transformation. The proposed method was applied to determine the rigid transformation between the stereo laparoscope and the robot manipulator. Promising experimental and simulation results have shown significant convergence speed improvement to 3 iterations from larger than 30 with regard to standard optimization method, which illustrates the effectiveness and efficiency of the proposed method.

  1. Eye-dominance, writing hand, and throwing hand.

    PubMed

    McManus, I C; Porac, C; Bryden, M P; Boucher, R

    1999-04-01

    Handedness and eye-dominance are undoubtedly associated statistically, although a previous meta-analysis has found that the precise relationship is difficult to explain, with about 35% of right-handers and 57% of left-handers being left eye dominant. Of particular difficulty to genetic or other models is that the proportions are distributed asymmetrically around 50%. The present study asked whether this complicated pattern of association occurred because, following Peters, it is necessary to divide right-and left-handers into consistent handers (who write and throw with the same hand) and inconsistent handers (who write and throw with opposite hands). In an analysis of 10,635 subjects from questionnaire studies, 28.8% of left-handers and 1.6% of right-handers by writing were inconsistent for throwing. Our results also showed that writing hand and throwing hand both relate independently to eyedness, that throwing hand is somewhat more strongly associated with eyedness, and that the awkward asymmetry around 50% is now removed, 24.2% of consistent right-handers being left eye dominant compared with 72.3% of consistent left-handers, and 55.4% of inconsistent right-handers compared with 47.0% of inconsistent left-handers. We conclude that eyedness is phenotypically secondary to writing and throwing handedness. In our discussion we note that eyedness runs in families, we present new data suggesting that writing hand and throwing hand are co-inherited, and we argue that further data are now required to model properly the associations of writing hand, throwing hand, and eyedness, as well as probably also footedness and language dominance.

  2. How your hand drives my eyes

    PubMed Central

    Ambrosini, Ettore; Cardellicchio, Pasquale; Sinigaglia, Corrado

    2014-01-01

    When viewing object-related hand actions people make proactive eye movements of the same kind as those made when performing such actions. Why is this so? It has been suggested that proactive gaze when viewing a given hand action depends on the recruitment of motor areas such as the ventral premotor (PMv) cortex that would be involved in the execution of that action. However, direct evidence for a distinctive role of the PMv cortex in driving gaze behavior is still lacking. We recorded eye moments while viewing hand actions before and immediately after delivering repetitive transcranial magnetic stimulation (rTMS) over the left PMv and the posterior part of the left superior temporal sulcus, which is known to be involved in high-order visual action processing. Our results showed that rTMS-induced effects were selective with respect to the viewed actions following the virtual lesion of the left PMv only. This, for the first time, provides direct evidence that the PMv cortex might selectively contribute to driving the viewer’s gaze to the action’s target. When people view another’s action, their eyes may be driven by motor processes similar to those they would need to perform the action themselves. PMID:23559593

  3. Dorsal Premotor Neurons Encode the Relative Position of the Hand, Eye, and Goal during Reach Planning

    PubMed Central

    Pesaran, Bijan; Nelson, Matthew J.; Andersen, Richard A.

    2011-01-01

    Summary When reaching to grasp an object, we often move our arm and orient our gaze together. How are these movements coordinated? To investigate this question, we studied neuronal activity in the dorsal premotor area (PMd) and the medial intraparietal area (area MIP) of two monkeys while systematically varying the starting position of the hand and eye during reaching. PMd neurons encoded the relative position of the target, hand, and eye. MIP neurons encoded target location with respect to the eye only. These results indicate that whereas MIP encodes target locations in an eye-centered reference frame, PMd uses a relative position code that specifies the differences in locations between all three variables. Such a relative position code may play an important role in coordinating hand and eye movements by computing their relative position. PMID:16815337

  4. Hand-eye and radial distortion calibration for rigid endoscopes.

    PubMed

    Malti, Abed; Barreto, Joao Pedro

    2013-12-01

    In this paper, we propose a non-linear calibration method for hand-eye system equipped with a camera undergoing radial distortion as the rigid endoscope. Whereas classic methods propose either a separated estimation of the camera intrinsics and the hand-eye transform or a mixed non-linear estimation of both hand-eye and camera intrinsics assuming a pin-hole model, the proposed approach enables a simultaneous refinement of the hand-eye and the camera parameters including the distortion factor with only three frames of the calibrated pattern. Our approach relies on three steps: (i) linear initial estimates of hand-eye and radial distortion with minimum number of frames: one single image to estimate the radial distortion and three frames to estimate the initial hand-eye transform, (ii) we propose to express the camera extrinsic with respect to hand-eye and world-grid transforms and (iii) we run bundle adjustment on the reprojection error with respect to the distortion parameters, the camera intrinsics and the hand-eye transform. Our method is quantitatively compared with state-of-the-art linear and non-linear methods. We show that our method provides a 3D reconstruction error of approximately 5% of the size of the 3D shape. Our experimental results show the effectiveness of simultaneously estimating hand-eye and distortion parameters for 3D reconstruction. Copyright © 2013 John Wiley & Sons, Ltd.

  5. Physiology and pathology of eye-head coordination.

    PubMed

    Proudlock, Frank Antony; Gottlob, Irene

    2007-09-01

    Human head movement control can be considered as part of the oculomotor system since the control of gaze involves coordination of the eyes and head. Humans show a remarkable degree of flexibility in eye-head coordination strategies, nonetheless an individual will often demonstrate stereotypical patterns of eye-head behaviour for a given visual task. This review examines eye-head coordination in laboratory-based visual tasks, such as saccadic gaze shifts and combined eye-head pursuit, and in common tasks in daily life, such as reading. The effect of the aging process on eye-head coordination is then reviewed from infancy through to senescence. Consideration is also given to how pathology can affect eye-head coordination from the lowest through to the highest levels of oculomotor control, comparing conditions as diverse as eye movement restrictions and schizophrenia. Given the adaptability of the eye-head system we postulate that this flexible system is under the control of the frontal cortical regions, which assist in planning, coordinating and executing behaviour. We provide evidence for this based on changes in eye-head coordination dependant on the context and expectation of presented visual stimuli, as well as from changes in eye-head coordination caused by frontal lobe dysfunction.

  6. Eye-Head Coordination for Visual Cognitive Processing

    PubMed Central

    Fang, Yu; Nakashima, Ryoichi; Matsumiya, Kazumichi; Kuriki, Ichiro; Shioiri, Satoshi

    2015-01-01

    We investigated coordinated movements between the eyes and head (“eye-head coordination”) in relation to vision for action. Several studies have measured eye and head movements during a single gaze shift, focusing on the mechanisms of motor control during eye-head coordination. However, in everyday life, gaze shifts occur sequentially and are accompanied by movements of the head and body. Under such conditions, visual cognitive processing influences eye movements and might also influence eye-head coordination because sequential gaze shifts include cycles of visual processing (fixation) and data acquisition (gaze shifts). In the present study, we examined how the eyes and head move in coordination during visual search in a large visual field. Subjects moved their eyes, head, and body without restriction inside a 360° visual display system. We found patterns of eye-head coordination that differed those observed in single gaze-shift studies. First, we frequently observed multiple saccades during one continuous head movement, and the contribution of head movement to gaze shifts increased as the number of saccades increased. This relationship between head movements and sequential gaze shifts suggests eye-head coordination over several saccade-fixation sequences; this could be related to cognitive processing because saccade-fixation cycles are the result of visual cognitive processing. Second, distribution bias of eye position during gaze fixation was highly correlated with head orientation. The distribution peak of eye position was biased in the same direction as head orientation. This influence of head orientation suggests that eye-head coordination is involved in gaze fixation, when the visual system processes retinal information. This further supports the role of eye-head coordination in visual cognitive processing. PMID:25799510

  7. Spatial and Temporal Eye–Hand Coordination Relies on the Parietal Reach Region

    PubMed Central

    Hauschild, Markus; Wilke, Melanie; Andersen, Richard A.

    2014-01-01

    Coordinated eye movements are crucial for precision control of our hands. A commonly believed neural mechanism underlying eye–hand coordination is interaction between the neural networks controlling each effector, exchanging, and matching information, such as movement target location and onset time. Alternatively, eye–hand coordination may result simply from common inputs to independent eye and hand control pathways. Thus far, it remains unknown whether and where either of these two possible mechanisms exists. A candidate location for the former mechanism, interpathway communication, includes the posterior parietal cortex (PPC) where distinct effector-specific areas reside. If the PPC were within the network for eye–hand coordination, perturbing it would affect both eye and hand movements that are concurrently planned. In contrast, if eye–hand coordination arises solely from common inputs, perturbing one effector pathway, e.g., the parietal reach region (PRR), would not affect the other effector. To test these hypotheses, we inactivated part of PRR in the macaque, located in the medial bank of the intraparietal sulcus encompassing the medial intraparietal area and area 5V. When each effector moved alone, PRR inactivation shortened reach but not saccade amplitudes, compatible with the known reach-selective activity of PRR. However, when both effectors moved concurrently, PRR inactivation shortened both reach and saccade amplitudes, and decoupled their reaction times. Therefore, consistent with the interpathway communication hypothesis, we propose that the planning of concurrent eye and hand movements causes the spatial information in PRR to influence the otherwise independent eye control pathways, and that their temporal coupling requires an intact PRR. PMID:25232123

  8. Crossed hand-eye dominance in male psychiatric patients.

    PubMed

    Giotakos, Orestis

    2002-12-01

    Increased incidence of left-eye and crossed hand-eye dominance have been considered as indicating left hemispheric dysfunction in many neuropsychiatric disorders. This study investigates the incidence of left-eye and crossed hand-eye dominance in patience with schizophrenia (n = 68), panic disorder (n = 62), personality disorder (n = 35), heroin addiction (n = 54), and mental retardation (n = 33), in comparison with controls (n = 944). All psychiatric groups, except the group with panic disorder, had significantly greater frequency of left-eye dominance than the control group. Furthermore, all psychiatric groups, except the personality-disordered group, had significantly greater frequency of crossed hand-eye dominance than the control group. These findings further support the evidence of an anomaly in hemispheric lateralization among different psychiatric populations, particularly among those with psychotic symptoms and cognitive deficits.

  9. Changes in Timing and kinematics of goal directed eye-hand movements in early-stage Parkinson’s disease

    PubMed Central

    2013-01-01

    Objective Many daily activities involve intrinsic or extrinsic goal-directed eye and hand movements. An extensive visuomotor coordination network including nigro-striatal pathways is required for efficient timing and positioning of eyes and hands. The aim of this study was to investigate how Parkinson’s disease (PD) affects eye-hand coordination in tasks with different cognitive complexity. Methods We used a touch screen, an eye-tracking device and a motion capturing system to quantify changes in eye-hand coordination in early-stage PD patients (H&Y < 2.5) and age-matched controls. Timing and kinematics of eye and hand were quantified in four eye-hand coordination tasks (pro-tapping, dual planning, anti-tapping and spatial memory task). Results In the pro-tapping task, saccade initiation towards extrinsic goals was not impaired. However, in the dual planning and anti-tapping task initiation of saccades towards intrinsic goals was faster in PD patients. Hand movements were differently affected: initiation of the hand movement was only delayed in the pro-tapping and dual planning task. Overall, hand movements in PD patients were slower executed compared to controls. Interpretation Whereas initiation of saccades in an extrinsic goal-directed task (pro-tapping task) is not affected, early stage PD patients have difficulty in suppressing reflexive saccades towards extrinsic goals in tasks where the endpoint is an intrinsic goal (e.g. dual planning and anti-tapping task). This is specific for eye movements, as hand movements have delayed responses in the pro-tapping and dual planning task. This suggests that reported impairment of the dorsolateral prefrontal cortex in early-stage PD patients affects only inhibition of eye movements. We conclude that timing and kinematics of eye and hand movements in visuomotor tasks are affected in PD patients. This result may have clinical significance by providing a behavioral marker for the early diagnosis of PD. PMID:23298720

  10. Oropharyngeal Control of Hand-Mouth Coordination in Newborn Infants.

    ERIC Educational Resources Information Center

    Rochat, Philippe; And Others

    1988-01-01

    Identifies a coordinative structure of action that integrates hand and mouth activities within hours after birth. Found that presenting neonates with a sucrose solution focused gross motor patterns of hand movement on the oral and perioral regions. (SKC)

  11. Solving the robot-world, hand-eye(s) calibration problem with iterative methods

    USDA-ARS?s Scientific Manuscript database

    Robot-world, hand-eye calibration is the problem of determining the transformation between the robot end effector and a camera, as well as the transformation between the robot base and the world coordinate system. This relationship has been modeled as AX = ZB, where X and Z are unknown homogeneous ...

  12. Eye-hand preference in schizophrenia: sex differences and significance for hand function.

    PubMed

    Liu, Yi-Chia; Yang, Yen Kuang; Lee, I Hui; Lin, Keh-Chung; Jeffries, Keith J; Lee, Li-Ching

    2004-06-01

    Hand preference and eye dominance were investigated in 73 (30 women, 43 men) schizophrenic patients and 71 (30 women, 41 men) healthy controls. There were significantly more schizophrenic patients and normal controls who were significantly right-hand dominant. However, schizophrenic patients showed a significant excess of left-eye dominance relative to controls (65.8% vs 29.6%; Odds Ratio= 4.75, p< .001). In addition, female schizophrenic patients showed a higher rate of nonright (either left or inconsistent) eye dominance (80%) than male schizophrenic patients (55.8%) and controls (33.3%). Analysis of hand performance on the Purdue Pegboard Test indicated that schizophrenic patients who showed crossed eye-hand dominance scored higher than did patients without crossed eye-hand dominance.

  13. Eye Control Deficits Coupled to Hand Control Deficits: Eye–Hand Incoordination in Chronic Cerebral Injury

    PubMed Central

    Rizzo, John-Ross; Fung, James K.; Hosseini, Maryam; Shafieesabet, Azadeh; Ahdoot, Edmond; Pasculli, Rosa M.; Rucker, Janet C.; Raghavan, Preeti; Landy, Michael S.; Hudson, Todd E.

    2017-01-01

    It is widely accepted that cerebral pathology can impair ocular motor and manual motor control. This is true in indolent and chronic processes, such as neurodegeneration and in acute processes such as stroke or those secondary to neurotrauma. More recently, it has been suggested that disruptions in these control systems are useful markers for prognostication and longitudinal monitoring. The utility of examining the relationship or the coupling between these systems has yet to be determined. We measured eye and hand-movement control in chronic, middle cerebral artery stroke, relative to healthy controls, in saccade-to-reach paradigms to assess eye–hand coordination. Primary saccades were initiated significantly earlier by stroke participants relative to control participants. However, despite these extremely early initial saccades to the target, reaches were nevertheless initiated at approximately the same time as those of control participants. Control participants minimized the time period between primary saccade onset and reach initiation, demonstrating temporal coupling between eye and hand. In about 90% of all trials, control participants produced no secondary, or corrective, saccades, instead maintaining fixation in the terminal position of the primary saccade until the end of the reach. In contrast, participants with stroke increased the time period between primary saccade onset and reach initiation. During this temporal decoupling, multiple saccades were produced in about 50% of the trials with stroke participants making between one and five additional saccades. Reaches made by participants with stroke were both longer in duration and less accurate. In addition to these increases in spatial reach errors, there were significant increases in saccade endpoint errors. Overall, the magnitude of the endpoint errors for reaches and saccades were correlated across participants. These findings suggest that in individuals with otherwise intact visual function, the

  14. Keep an Eye on the Hand

    ERIC Educational Resources Information Center

    Zoller, Kendall

    2004-01-01

    Nonverbal communication--how we use our voices, breathing, bodies, and eyes--is as powerful as our words. As much as 82% of our message is conveyed through nonverbal strategies. Learning to use these cues can be key to improving our ability to facilitate or lead meetings.

  15. Parieto-frontal gradients and domains underlying eye and hand operations in the action space.

    PubMed

    Battaglia-Mayer, Alexandra; Babicola, Lucy; Satta, Eleonora

    2016-10-15

    In monkeys, motor intention in its different forms emerges from a parietal-frontal gradient of visual, eye and hand signals, containing discrete dominant domains. These are formed by areas sharing cortical connections and functional properties. Within this gradient, the combination of different inputs determines the tuning properties of neurons, while local and long cortico-cortical connections shape the structure and temporal delays of the network. The pathways linking similar functional domains in parietal and frontal cortex sculpt information processing systems related to different functions, all requiring eye-hand coordination. fMRI experiments show that similar gradients lay at the core of cognitive-motor control in humans as well. This eye-hand matrix provides a framework to address, within a unitary frame, not only basic forms of motor behavior, such as reaching and grasping, but also actions of increasing complexity, such as interception of moving targets, tool use, construction of complex objects, maze analysis and solution, among others. The organization of the cerebral cortex into functional gradients and domains, beyond frontal and parietal cortices, is common to other brain regions, such as prefrontal cortex and hippocampus, and does not support views of the parieto-frontal operations based on specific and strictly segregated eye and hand modules. These can only be found at the eye and hand motor output domains in the frontal cortex, that is in the frontal eye fields and in the primary motor cortex, respectively. Copyright © 2016. Published by Elsevier Ltd.

  16. Bimanual coordination with three hands: is the mirror hand of any help?

    PubMed

    Metral, Morgane; Guinot, Marine; Bresciani, Jean-Pierre; Luyat, Marion; Roulin, Jean-Luc; Guerraz, Michel

    2014-01-01

    The mirror paradigm has been used extensively both as a research tool for studying kinesthesia in healthy individuals and as a therapeutic tool for improving recovery and/or alleviating symptoms in patients. The present study of healthy participants assessed the contribution of the mirror paradigm to motor control in a bimanual coordination task performed under sensorimotor disturbance conditions. In Experiment 1, the participants were required to produce symmetrical circles with both hands/arms at the same time. In Experiment 2, the task consisted of synchronous extension-flexion movements of both arms in the sagittal plane. These tasks were performed under four different visual conditions: (i) mirror vision (i.e. with the non-dominant arm reflected in a mirror--the third hand--and the dominant arm hidden), (ii) full vision (i.e. both arms visible), (iii) with only the non-dominant arm visible and (iv) with the eyes closed. In Experiments 1 and 2, sensorimotor disturbance was applied to the participant's dominant arm by co-vibrating antagonistic muscles (the biceps and the triceps). In the complex circle drawing task, bimanual performance was better in the mirror condition than when participants saw their non-dominant arm only. However, motor performance in the mirror vision condition was little better than in the eyes closed condition, regardless of whether or not sensorimotor disturbance was applied. In Experiment 2, there were no differences between the "eyes closed" and "mirror vision" conditions. Although mirror reflection of one arm has been shown to induce consistent, vivid, perceptual illusions (kinesthetic illusion), our results suggest that it is less effective in modulating motor behavior.

  17. Exploring hand coordination as a measure of surgical skill.

    PubMed

    Law, Katherine E; Jenewein, Caitlin G; Gannon, Samantha J; DiMarco, Shannon M; Maulson, Lakita J; Laufer, Shlomi; Pugh, Carla M

    2016-09-01

    The study aim was to identify residents' coordination between dominant and nondominant hands while grasping for sutures in a laparoscopic ventral hernia repair procedure simulation. We hypothesize residents will rely on their dominant and nondominant hands unequally while grasping for suture. Surgical residents had 15 min to complete the mesh securing and mesh tacking steps of a laparoscopic ventral hernia repair procedure. Procedure videos were coded for manual coordination events during the active suture grasping phase. Manual coordination events were defined as: active motion of dominant, nondominant, or both hands; and bimanual or unimanual manipulation of hands. A chi-square test was used to discriminate between coordination choices. Thirty-six residents (postgraduate year, 1-5) participated in the study. Residents changed manual coordination types during active suture grasping 500 times, ranging between 5 and 24 events (M = 13.9 events, standard deviation [SD] = 4.4). Bimanual coordination was used most (40%) and required the most time on average (M = 20.6 s, SD = 27.2), while unimanual nondominant coordination was used least (2.2%; M = 7.9 s, SD = 6.9). Residents relied on their dominant and nondominant hands unequally (P < 0.001). During 24% of events, residents depended on their nondominant hand (n = 120), which was predominantly used to operate the suture passer device. Residents appeared to actively coordinate both dominant and nondominant hands almost half of the time to complete suture grasping. Bimanual task durations took longer than other tasks on average suggesting these tasks were characteristically longer or switching hands required a greater degree of coordination. Future work is necessary to understand how task completion time and overall performance are affected by residents' hand utilization and switching between dominant and nondominant hands in surgical tasks. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Deficits of hand coordination and laterality of carotid endarterectomy.

    PubMed

    Heyer, Eric J; Mallon, Kaitlin A; Mergeche, Joanna L; Stern, Yaakov; Connolly, E Sander

    2015-01-01

    Neurocognitive performance is used to assess multiple cognitive domains, including motor coordination, before and after carotid endarterectomy (CEA). Although gross motor strength is impaired with ischemia of large cortical areas or of the internal capsule, the authors hypothesize that patients undergoing CEA demonstrate significant motor deficits of hand coordination contralateral to the operative side, which is more clearly manifest in the nondominant hand than in the dominant hand with ischemia of smaller cortical areas. The neurocognitive performance of 374 patients was evaluated with a battery of neuropsychometric tests. Both asymptomatic and symptomatic patients undergoing CEA were included. The authors evaluated the patients' dominant and nondominant hand performance on the Grooved Pegboard test, a test of hand coordination, to demonstrate their functional laterality. Neurocognitive dysfunction was evaluated as the difference in performance before and after CEA according to group-rate and event-rate analyses. The z scores were generated for all tests using a reference group of patients who were having simple spine surgery. Dominant and nondominant motor coordination functions were evaluated as raw scores and as calculated z scores. According to event-rate analysis, significantly more patients undergoing CEA of the opposite carotid artery demonstrated nondominant than dominant hand deficits of coordination (41.2% vs 26.4%, respectively, p = 0.02). Similarly, according to group-rate analysis, in patients undergoing CEA of the opposite carotid artery, raw difference scores from the Grooved Pegboard test reflected greater nondominant than dominant hand deficits of coordination (21.0 ± 54.4 vs 9.7 ± 37.0, respectively, p = 0.02). Patients undergoing CEA of the opposite carotid artery are more likely to demonstrate nondominant than dominant hand deficits of coordination because of greater dexterity in the dominant hand before surgery.

  19. [Bionic model for coordinated head-eye motion control].

    PubMed

    Mao, Xiaobo; Chen, Tiejun

    2011-10-01

    The relationships between eye movements and head movements of the primate during gaze shifts are analyzed in detail in the present paper. Applying the mechanisms of neurophysiology to engineering domain, we have improved the robot eye-head coordination. A bionic control strategy of coordinated head-eye motion was proposed. The processes of gaze shifts are composed of an initial fast phase followed by a slow phase. In the fast phase saccade eye movements and slow head movements were combined, which cooperate to bring gaze from an initial resting position toward the new target rapidly, while in the slow phase the gaze stability and target fixation were ensured by the action of the vestibulo-ocular reflex (VOR) where the eyes and head rotate by equal amplitudes in opposite directions. A bionic gaze control model was given. The simulation results confirmed the effectiveness of the model by comparing with the results of neurophysiology experiments.

  20. [The problem of crossed eye-hand dominance (author's transl)].

    PubMed

    Niederlandová, Z

    1975-06-01

    The manual and visual dominance of one side has in recent times attracted much attention from many aspects. Crossed dominance (right eye - left hand) seems significant in strabismus of childhood. For the first time recently it has become obvious, that the structure of the body and its muscles, especially of the trunk is asymmetrical. Even in normal persons the centre of gravity of the body is not in the midline, but displaced usually some distance to the left. We have examined the stabilographic proportions in 30 normal and 30 squinting children. In the normal children, with closed eyes the centre of gravity of the body was displaced in 80% to the right, in the quinting children this point was in 73% displaced to the left. We can deduce from this, that the marked right-eye dominance in squinting children is responsible for the displacement of the centre of gravity. If the right eye is open, then the vertical body-axis tends a little to the left. This tendency demands an increase of muscle tone on the left side of the body and with this a displacement of the body centre of gravity to the left; this not only, when the right eye is open, but also, when both eyes are opened or closed. From our experience this adjustment is especially suited to normalise the working together of the hand and the eye in squinting children.

  1. Effect of hand paddles and parachute on butterfly coordination.

    PubMed

    Telles, Thiago; Barroso, Renato; Barbosa, Augusto Carvalho; Salgueiro, Diego Fortes de Souza; Colantonio, Emilson; Andries Júnior, Orival

    2015-01-01

    This study investigated the effects of hand paddles, parachute and hand paddles plus parachute on the inter-limb coordination of butterfly swimming. Thirteen male swimmers were evaluated in four random maximal intensity conditions: without equipment, with hand paddles, with parachute and with hand paddles + parachute. Arm and leg stroke phases were identified by 2D video analysis to calculate the total time gap (T1: time between hands' entry in the water and high break-even point of the first undulation; T2: time between the beginning of the hand's backward movement and low break-even point of the first undulation; T3: time between the hand's arrival in a vertical plane to the shoulders and high break-even point of the second undulation; T4: time between the hand's release from the water and low break-even point of the second undulation). The swimming velocity was reduced and T1, T2 and T3 increased in parachute and hand paddles + parachute. No changes were observed in T4. Total time gap decreased in parachute and hand paddles + parachute. It is concluded that hand paddles do not influence the arm-to-leg coordination in butterfly, while parachute and hand paddles + parachute do change it, providing a greater propulsive continuity.

  2. Upper limb and eye movement coordination during reaching tasks in people with stroke.

    PubMed

    Meadmore, Katie L; Exell, Timothy A; Burridge, Jane H; Hughes, Ann-Marie; Freeman, Christopher T; Benson, Valerie

    2017-06-09

    To enhance understanding of the relationship between upper limb and eye movements during reaching tasks in people with stroke. Eye movements were recorded from 10 control participants and 8 chronic stroke participants during a visual orienting task (Experiment 1) and a series of reaching tasks (Experiment 2). Stroke participants completed the reaching tasks using (i) their less impaired upper limb, (ii) their more impaired upper limb without support, and (iii) their more impaired upper limb, with support (SaeboMAS gravitational support and/or electrical stimulation). Participants were tested individually and completed both experiments in the same session. Oculomotor control and the coordination between the upper limb and the oculomotor system were found to be intact in stroke participants when no limb movements were required, or when the less impaired upper limb was used. However, when the more impaired upper limb was used, success and accuracy in reaching decreased and patterns of eye movements changed, with an observed increase in eye movements to the limb itself. With upper limb support, patterns of hand-eye coordination were found to more closely resemble those of the control group. Deficits in upper limb motor systems result in changes in patterns of eye movement behavior during reaching tasks. These changes in eye movement behavior can be modulated by providing upper limb support. Implications for Rehabilitation Deficits in upper limb motor systems can result in changes in patterns of eye movement behavior during reaching tasks. Upper limb support can reduce deficits in hand-eye coordination. Stroke rehabilitation outcomes should consider motor and oculomotor performance.

  3. Hand-Eye Calibration in Visually-Guided Robot Grinding.

    PubMed

    Li, Wen-Long; Xie, He; Zhang, Gang; Yan, Si-Jie; Yin, Zhou-Ping

    2016-11-01

    Visually-guided robot grinding is a novel and promising automation technique for blade manufacturing. One common problem encountered in robot grinding is hand-eye calibration, which establishes the pose relationship between the end effector (hand) and the scanning sensor (eye). This paper proposes a new calibration approach for robot belt grinding. The main contribution of this paper is its consideration of both joint parameter errors and pose parameter errors in a hand-eye calibration equation. The objective function of the hand-eye calibration is built and solved, from which 30 compensated values (corresponding to 24 joint parameters and six pose parameters) are easily calculated in a closed solution. The proposed approach is economic and simple because only a criterion sphere is used to calculate the calibration parameters, avoiding the need for an expensive and complicated tracking process using a laser tracker. The effectiveness of this method is verified using a calibration experiment and a blade grinding experiment. The code used in this approach is attached in the Appendix.

  4. Reaching in depth: hand position dominates over binocular eye position in the rostral superior parietal lobule.

    PubMed

    Ferraina, Stefano; Brunamonti, Emiliano; Giusti, Maria Assunta; Costa, Stefania; Genovesio, Aldo; Caminiti, Roberto

    2009-09-16

    Neural activity was recorded in area PE (dorsorostral part of Brodmann's area 5) of the posterior parietal cortex while monkeys performed arm reaching toward memorized targets located at different distances from the body. For any given distance, arm movements were performed while the animal kept binocular eye fixation constant. Under these conditions, the activity of a large proportion (36%) of neurons was modulated by reach distance during the memory period. By varying binocular eye position (vergence angle) and initial hand position, we found that the reaching-related activity of most neurons (61%) was influenced by changing the starting position of the hand, whereas that of a smaller, although substantial, population (13%) was influenced by changes of binocular eye position (i.e., by the angle of vergence). Furthermore, the modulation of the neural activity was better explained expressing the reach movement end-point, corresponding to the memorized target location, in terms of distance from the initial hand position, rather than from the body. These results suggest that the activity of neurons in area PE combines information about eye and hand position to encode target distance for reaching in depth predominantly in hand coordinates. This encoding mechanism is consistent with the position of PE in the functional gradient that characterizes the parieto-frontal network underlying reaching.

  5. Hand-head coordination changes from discrete to reciprocal hand movements for various difficulty settings.

    PubMed

    Germain-Robitaille, Mathieu; Terrier, Romain; Forestier, Nicolas; Teasdale, Normand

    2012-07-11

    The parameters dictating the temporal hand-head coordination during visually corrected movements remain elusive. Here we examine the effects of the nature (discrete vs reciprocal) and the difficulty (ID of 4.7, 5.7 and 6.7 bits) of the task on the temporal hand-head coordination during a Fitts' like paradigm. Subjects aimed at a single target (discrete movement) or alternately to two targets (reciprocal movements). Head movements were unaffected by the ID during discrete movements. This was not the case during reciprocal movements where they were (1) smaller in duration and amplitude than during discrete movements and (2) increased in duration and amplitude with an increasing ID. To measure the temporal hand-head coordination, hand-head latencies were calculated at the onset, peak speed and offset of each movement. Offset latencies remained positive (i.e. the hand reached the target after the head stopped) for all IDs during reciprocal but not during discrete movements. Altogether, different patterns of temporal hand-head coordination were observed between discrete and reciprocal movements as well as between IDs, suggesting the hand-head coordination does not follow a fixed rule but is adjusted to task requirements.

  6. Eye tracking a self-moved target with complex hand-target dynamics

    PubMed Central

    Landelle, Caroline; Montagnini, Anna; Madelain, Laurent

    2016-01-01

    Previous work has shown that the ability to track with the eye a moving target is substantially improved when the target is self-moved by the subject's hand compared with when being externally moved. Here, we explored a situation in which the mapping between hand movement and target motion was perturbed by simulating an elastic relationship between the hand and target. Our objective was to determine whether the predictive mechanisms driving eye-hand coordination could be updated to accommodate this complex hand-target dynamics. To fully appreciate the behavioral effects of this perturbation, we compared eye tracking performance when self-moving a target with a rigid mapping (simple) and a spring mapping as well as when the subject tracked target trajectories that he/she had previously generated when using the rigid or spring mapping. Concerning the rigid mapping, our results confirmed that smooth pursuit was more accurate when the target was self-moved than externally moved. In contrast, with the spring mapping, eye tracking had initially similar low spatial accuracy (though shorter temporal lag) in the self versus externally moved conditions. However, within ∼5 min of practice, smooth pursuit improved in the self-moved spring condition, up to a level similar to the self-moved rigid condition. Subsequently, when the mapping unexpectedly switched from spring to rigid, the eye initially followed the expected target trajectory and not the real one, thereby suggesting that subjects used an internal representation of the new hand-target dynamics. Overall, these results emphasize the stunning adaptability of smooth pursuit when self-maneuvering objects with complex dynamics. PMID:27466129

  7. Eye tracking a self-moved target with complex hand-target dynamics.

    PubMed

    Landelle, Caroline; Montagnini, Anna; Madelain, Laurent; Danion, Frederic

    2016-10-01

    Previous work has shown that the ability to track with the eye a moving target is substantially improved when the target is self-moved by the subject's hand compared with when being externally moved. Here, we explored a situation in which the mapping between hand movement and target motion was perturbed by simulating an elastic relationship between the hand and target. Our objective was to determine whether the predictive mechanisms driving eye-hand coordination could be updated to accommodate this complex hand-target dynamics. To fully appreciate the behavioral effects of this perturbation, we compared eye tracking performance when self-moving a target with a rigid mapping (simple) and a spring mapping as well as when the subject tracked target trajectories that he/she had previously generated when using the rigid or spring mapping. Concerning the rigid mapping, our results confirmed that smooth pursuit was more accurate when the target was self-moved than externally moved. In contrast, with the spring mapping, eye tracking had initially similar low spatial accuracy (though shorter temporal lag) in the self versus externally moved conditions. However, within ∼5 min of practice, smooth pursuit improved in the self-moved spring condition, up to a level similar to the self-moved rigid condition. Subsequently, when the mapping unexpectedly switched from spring to rigid, the eye initially followed the expected target trajectory and not the real one, thereby suggesting that subjects used an internal representation of the new hand-target dynamics. Overall, these results emphasize the stunning adaptability of smooth pursuit when self-maneuvering objects with complex dynamics. Copyright © 2016 the American Physiological Society.

  8. Intentional and attentional dynamics of speech-hand coordination.

    PubMed

    Treffner, Paul; Peter, Mira

    2002-12-01

    Interest is rapidly growing in the hypothesis that natural language emerged from a more primitive set of linguistic acts based primarily on manual activity and hand gestures. Increasingly, researchers are investigating how hemispheric asymmetries are related to attentional and manual asymmetries (i.e., handedness). Both speech perception and production have origins in the dynamical generative movements of the vocal tract known as articulatory gestures. Thus, the notion of a "gesture" can be extended to both hand movements and speech articulation. The generative actions of the hands and vocal tract can therefore provide a basis for the (direct) perception of linguistic acts. Such gestures are best described using the methods of dynamical systems analysis since both perception and production can be described using the same commensurate language. Experiments were conducted using a phase transition paradigm to examine the coordination of speech-hand gestures in both left- and right-handed individuals. Results address coordination (in-phase vs. anti-phase), hand (left vs. right), lateralization (left vs. right hemisphere), focus of attention (speech vs. tapping), and how dynamical constraints provide a foundation for human communicative acts. Predictions from the asymmetric HKB equation confirm the attentional basis of functional asymmetry. Of significance is a new understanding of the role of perceived synchrony (p-centres) during intentional cases of gestural coordination. Copyright 2003 Elsevier Science B.V.

  9. Line bisection by eye and by hand reveal opposite biases.

    PubMed

    Leonards, Ute; Stone, Samantha; Mohr, Christine

    2013-08-01

    The vision-for-action literature favours the idea that the motor output of an action-whether manual or oculomotor-leads to similar results regarding object handling. Findings on line bisection performance challenge this idea: healthy individuals bisect lines manually to the left of centre and to the right of centre when using eye fixation. In case that these opposite biases for manual and oculomotor action reflect more universal compensatory mechanisms that cancel each other out to enhance overall accuracy, one would like to observe comparable opposite biases for other material. In the present study, we report on three independent experiments in which we tested line bisection (by hand, by eye fixation) not only for solid lines, but also for letter lines; the latter, when bisected manually, is known to result in a rightward bias. Accordingly, we expected a leftward bias for letter lines when bisected via eye fixation. Analysis of bisection biases provided evidence for this idea: manual bisection was more rightward for letter as compared to solid lines, while bisection by eye fixation was more leftward for letter as compared to solid lines. Support for the eye fixation observation was particularly obvious in two of the three studies, for which comparability between eye and hand action was increasingly adjusted (paper-pencil versus touch screen for manual action). These findings question the assumption that ocular motor and manual output are always inter-changeable, but rather suggest that at least for some situations ocular motor and manual output biases are orthogonal to each other, possibly balancing each other out.

  10. Eye-hand laterality and right thoracic idiopathic scoliosis.

    PubMed

    Catanzariti, Jean-François; Guyot, Marc-Alexandre; Agnani, Olivier; Demaille, Samantha; Kolanowski, Elisabeth; Donze, Cécile

    2014-06-01

    The adolescent idiopathic scoliosis (AIS) pathogenesis remains unknown. Certain studies have shown that there is a correlation between manual laterality and scoliotic deviation. A full study of manual laterality needs to be paired with one for visual dominance. With the aim of physiopathological research, we have evaluated the manual and visual laterality in AIS. A retrospective study from prospective data collection is used to evaluate the distribution of eye-hand laterality (homogeneous or crossed) of 65 right thoracic AIS (mean age 14.8 ± 1.8 years; mean Cobb angle: 32.8°) and a control group of 65 sex and age-matched (mean age 14.6 ± 1.8 years). The manual laterality was defined by the modified Edinburgh Handedness Inventory. The evaluation of the visual laterality is done using three tests (kaleidoscope test, hole-in-the-card test, distance-hole-in-the-card test). The group of right thoracic AIS presents a significantly higher frequency of crossed eye-hand laterality (63 %) than the control group (63 vs. 29.2 %; p < 0.001). In the AIS group, the most frequent association, within crossed laterality is "right hand dominant-left eye dominant" (82.9 %). There is no relationship with the Cobb angle. Those with right thoracic AIS show a higher occurrence of crossed eye-hand laterality. This could point physiopathological research of AIS towards functional abnormality of the optic chiasma through underuse of cross visual pathways, and in particular accessory optic pathways. It would be useful to explore this by carrying out research on AISs through neuroimaging and neurofunctional exploration.

  11. Processing coordinate structures in Chinese: evidence from eye movements.

    PubMed

    Qingrong, Chen; Yan, Huang

    2012-01-01

    This article reports the results of an eye-tracking experiment that investigated the processing of coordinate structures in Chinese sentence comprehension. The study tracked the eye movements of native Chinese readers as they read sentences consisting of two independent clauses connected by the word huo zhe. The data strongly confirmed readers' preference for an initial noun phrase (NP)-coordination parsing in Chinese coordination structure. When huo zhe was absent from the beginning of a sentence, we identified a cost associated with abandoning the NP-coordination analysis, which was evident with regard to the second NP when the coordination was unambiguous. Otherwise, this cost was evident with regard to the verb, the syntactically disambiguating region, when the coordination was ambiguous. However, the presence of a sentence-initial huo zhe reduced reading times and regressions in the huo zhe NP and the verb regions. We believe that the word huo zhe at the beginning of a sentence helps the reader predict that the sentence contains a parallel structure. Before the corresponding phrases appear, the readers can use the word huo zhe and the language structure thereafter to predicatively construct the syntactic structure. Such predictive capability can eliminate the reader's preference for NP-coordination analysis. Implications for top-down parsing theory and models of initial syntactic analysis and reanalysis are discussed.

  12. Relationship between eye preference and binocular rivalry, and between eye-hand preference and reading ability in children.

    PubMed

    Fagard, J; Monzalvo-Lopez, K; Mamassian, P

    2008-12-01

    One goal of the experiment presented here was to check, in children, the relationship between eye preference when sighting at different angles and eye dominance in binocular rivalry. In addition, since it is sometimes argued that a crossed pattern of eye-hand preference might put children at risk of difficulties in learning to read, we evaluated the relationship between this pattern and reading achievement in first and sixth graders. Results showed that a majority of children are right-eyed for monosighting, and that intrinsic preference and spatial factor influence the choice of eye. As many children were right- or left-eye dominant, and eye dominance was not related to eye preference. We found no relationship between eye-hand preference and reading proficiency, thus not confirming that a crossed pattern of eye-hand preference might put children at risk of difficulties in learning to read. Consistent handers were more advanced in reading than inconsistent handers.

  13. Hand preferences for bimanual coordination in 29 bonobos (Pan paniscus).

    PubMed

    Chapelain, Amandine S; Hogervorst, Eef

    2009-01-03

    Brain lateralization has long been thought to be unique to humans. To investigate the origins and functions of this feature, researchers study behavioural laterality in other animals. Despite a substantial database, manual laterality in non-human primates remains a controversial topic. We give here a review of the main findings on manual preference in great apes. This article presents data on hand preferences for a bimanual coordination in 29 bonobos (Pan paniscus). The study aims to provide data on manual laterality for a complex bimanual task in this very interesting and rarely studied species. Hand preferences were assessed using the 'tube task'. This task has been used with other species, which allows reliable data comparisons. The task requires a bimanual coordinated precise action: the subject holds the tube with one hand while reaching for food inside with the other hand. As a complex task, this measure has been shown to be efficient in revealing hand preferences. It has revealed group-level right bias in chimpanzees. Bonobos had never been tested. We recorded both independent bouts (counting only the first pattern of a sequence of identical actions) and frequency (counting every action). The bonobos exhibited strong hand preferences. With frequency, 11 bonobos were classified as right-handed, 15 were left-handed and 3 had no preference. With bouts, 8 bonobos were right-handed, 9 were left-handed and 12 had no preference. No group-level bias appeared. The results are discussed in relation with previous findings and theories on brain lateralization.

  14. Automated tracking and grasping of a moving object with a robotic hand-eye system

    SciTech Connect

    Allen, P.K.; Timcenko, A.; Yoshimi, B.; Michelman, P. . Dept. of Computer Science)

    1993-04-01

    Most robotic grasping tasks assume a stationary or fixed object. In this paper, the authors explore the requirements for tracking and grasping a moving object. The focus of the work is to achieve a high level of interaction between a real-time vision system capable of tracking moving objects in 3-D and a robot arm with gripper that can be used to pick up a moving object. There is an interest in exploring the interplay of hand--eye coordination for dynamic grasping takes such as grasping of parts on a moving conveyor system, assembly of articulated parts, or for grasping from a mobile robotic system. Coordination between an organisms sensing modalities and motor control system is a hallmark of intelligent behavior, and they are pursuing the goal of building an integrated sensing and actuation system that can operate in dynamic as opposed to static environments. The system they have built addresses three distinct problems in robotic hand--eye coordination for grasping moving objects: fast computation of 3-D motion parameters from vision, predictive control of a moving robotic arm to track a moving object, and interception and grasping. The system is able to operate at approximately human arm movement rates, and experimental results in which a moving model train is tracked is presented, stably grasped, and picked up by the system. The algorithms they have developed that relate sensing to actuation are quite general and applicable to a variety of complex robotic tasks that require visual feedback for arm and hand control.

  15. Out of your hand's reach, out of my eyes' reach.

    PubMed

    Costantini, Marcello; Ambrosini, Ettore; Sinigaglia, Corrado

    2012-01-01

    When witnessing another's action, people recruit the same motor resources that enable them to efficiently perform that action, thus gazing at its target well before the agent's hand. But just to what extent does this recruitment help people in grabbing another's action target? If the latter seems to be out of the agent's reach, will this impact on people's gaze behaviour? We recorded proactive eye movements while participants witnessed someone else trying to reach for and grasp objects located either within or outside his reach. Proactivity of gaze was impaired when the targets were just out of the agent's reach. This effect is likely to be due to an interpersonal bodily space representation that allows one to map another's reaching space, thus prompting proactive eye movements towards the target just in case the agent is in the position to act upon it.

  16. Keratoconus, allergy, itch, eye-rubbing and hand-dominance.

    PubMed

    McMonnies, Charles W; Boneham, Gavin C

    2003-11-01

    One hypothesis for the pathogenesis of keratoconus includes teenage allergy, ocular itch and associated eye-rubbing. This study examined the prevalence of these factors for teenage and adult patients. The results for a sample of 53 subjects with bilateral keratoconus were compared with those for a control sample of non-keratoconus subjects, who also routinely wore RGP contact lenses. The strongest dominant hand and the eye with more advanced keratoconus were also determined, to examine for a relationship between them. The keratoconic sample reported significantly higher levels of allergy, itch and rubbing as teenagers and as adults. However, all distributions were bimodal, consistent with the hypothesis that allergy, itch and rubbing are relevant in the pathogenesis of keratoconus only when the highest levels of these factors are present. For example, a significant relationship between the stronger dominant hand and the more advanced eye was evident only in subjects who reported the most severe rubbing. This finding adds weight to the circumstantial evidence that rubbing contributes to the pathogenesis of keratoconus. Low levels of teenage rubbing by some keratoconic subjects suggest a non-rubbing pathogenesis and that emphasis on rubbing management is not warranted in these cases. However, high levels of adult rubbing reported by many keratoconic subjects indicate that the standard advice to avoid vigorous and prolonged rubbing is often not effective, even when repeated. There appears to be an indication for the need to improve the management of eye-rubbing for some patients with keratoconus or at risk of developing this disease.

  17. Eye and hand movement strategies in older adults during a complex reaching task.

    PubMed

    Coats, Rachel O; Fath, Aaron J; Astill, Sarah L; Wann, John P

    2016-02-01

    The kinematics of upper limb movements and the coordination of eye and hand movements are affected by ageing. These age differences are exacerbated when task difficulty is increased, but the exact nature of these differences remains to be established. We examined the performance of 12 older adults (mean age = 74) and 11 younger adults (mean age = 20) on a multi-phase prehension task. Participants had to reach for a target ball with their preferred hand, pick it up and place it in a tray, then reach for a second target ball and place that in the same tray. On half the trials (stabilising condition), participants were required to hold the tray just above the surface of the table with their non-preferred hand and keep it as still as possible. Hand and eye movements were recorded. Older adults took longer to complete their movements and reached lower peak velocities than the younger adults. Group differences were most apparent in the stabilising condition, suggesting that the added complexity had a greater effect on the performance of the older adults than the young. During pickup, older adults preferred to make an eye movement to the next target as soon as possible, but spent longer fixating the current target during placement, when accuracy requirements were higher. These latter observations suggest that older adults employed a task-dependent eye movement strategy, looking quickly to the next target to allow more time for planning and execution when possible, but fixating on their hand and successful placement of the ball when necessary.

  18. Hand preference in children with developmental coordination disorders: cause and effect?

    PubMed

    Sigmundsson, H; Whiting, H T A

    2002-06-01

    Inter- and intra-modal matching by eight-year-old children diagnosed as having hand-eye coordination problems (HECP) and categorized as left-handed, together with a left-handed control group of children without such problems, were tested using a manual sensory matching task. The task required the children to locate target pins, visually (seen target), proprioceptively (felt target) or in combination (felt and seen target), while matching to the located target was always carried out without vision. Performance was superior when the target was located visually or visually/proprioceptively for both groups of children. These results question the conclusion that intra-modal will always be more accurate than inter-modal matching. When the combined scores for both hands were analyzed, the HECP children showed inferior performance to the control children in both inter- and intra-modal matching. Separate right and left hand analyses, demonstrated that the differences between the HECP group and control children could be accounted for by lowered performances when the right hand (nonpreferred) was used to match the located target position. Putative neurological disorders related to the development of the hemisphere controlling the nonpreferred hand (left hemisphere) are invoked to account for the poor performance with the nonpreferred hand of the HECP children.

  19. Dimensionality reduction in control and coordination of the human hand.

    PubMed

    Vinjamuri, Ramana; Sun, Mingui; Chang, Cheng-Chun; Lee, Heung-No; Sclabassi, Robert J; Mao, Zhi-Hong

    2010-02-01

    The concept of kinematic synergies is proposed to address the dimensionality reduction problem in control and coordination of the human hand. This paper develops a method for extracting kinematic synergies from joint-angular-velocity profiles of hand movements. Decomposition of a limited set of synergies from numerous movements is a complex optimization problem. This paper splits the decomposition process into two stages. The first stage is to extract synergies from rapid movement tasks using singular value decomposition (SVD). A bank of template functions is then created from shifted versions of the extracted synergies. The second stage is to find weights and onset times of the synergies based on l(1) -minimization, whose solutions provide sparse representations of hand movements using synergies.

  20. Kinematic property of target motion conditions gaze behavior and eye-hand synergy during manual tracking.

    PubMed

    Huang, Chien-Ting; Hwang, Ing-Shiou

    2013-12-01

    This study investigated how frequency demand and motion feedback influenced composite ocular movements and eye-hand synergy during manual tracking. Fourteen volunteers conducted slow and fast force-tracking in which targets were displayed in either line-mode or wave-mode to guide manual tracking with target movement of direct position or velocity nature. The results showed that eye-hand synergy was a selective response of spatiotemporal coupling conditional on target rate and feedback mode. Slow and line-mode tracking exhibited stronger eye-hand coupling than fast and wave-mode tracking. Both eye movement and manual action led the target signal during fast-tracking, while the latency of ocular navigation during slow-tracking depended on the feedback mode. Slow-tracking resulted in more saccadic responses and larger pursuit gains than fast-tracking. Line-mode tracking led to larger pursuit gains but fewer and shorter gaze fixations than wave-mode tracking. During slow-tracking, incidences of saccade and gaze fixation fluctuated across a target cycle, peaking at velocity maximum and the maximal curvature of target displacement, respectively. For line-mode tracking, the incidence of smooth pursuit was phase-dependent, peaking at velocity maximum as well. Manual behavior of slow or line-mode tracking was better predicted by composite eye movements than that of fast or wave-mode tracking. In conclusion, manual tracking relied on versatile visual strategies to perceive target movements of different kinematic properties, which suggested a flexible coordinative control for the ocular and manual sensorimotor systems. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Effects of eye dominance (left vs. right) and cannabis use on intermanual coordination and negative symptoms in schizophrenia patients.

    PubMed

    Gorynia, Inge; Schwaiger, Markus; Heinz, Andreas

    2014-12-01

    Based on the previous findings, it has been assumed that in schizophrenia patients, eye dominance and cannabis use will affect negative symptoms and intermanual coordination (IMC), an index of interhemispheric communication. But eye dominance, specifically the clinical findings for it, has been neglected in schizophrenia research. We therefore investigated its effects in 52 right-handed (36 right-eyed and 16 left-eyed) and 51 left-handed (35 left-eyed and 16 right-eyed) schizophrenia in-patients without and with drug use. Eye dominance affected IMC in all schizophrenia patients. When comparing right- and left-handers, we found that this result was only significant in the right-handed patients and in the smaller subgroup without drug use. In the right-handers, left eye dominance-like left-handedness-was associated with higher values in IMC and less pronounced manifestation of negative symptoms, right eye dominance was not. Thus, left-eyed right-handers may be more closely related to left-handers than to right-handers. In accordance with the results from the literature, we suggest that these findings are due to better interhemispheric connections and less impairment of white matter structures, especially in right-hemispheric regions. Moreover, cannabis use was related to higher scores in IMC and less pronounced negative symptoms, but only in the right-eyed and not in the left-eyed right-handers or in the left-handers. Hence, differences in eye dominance and handedness may be partially responsible for different results in interhemispheric connections among cannabis users. In conclusion, both eye dominance and use of cannabis should be taken into account when assessing clinical symptoms in schizophrenia patients.

  2. Eye–Hand Coordination Skills in Children with and without Amblyopia

    PubMed Central

    Suttle, Catherine M.; Melmoth, Dean R.; Finlay, Alison L.; Sloper, John J.

    2011-01-01

    Purpose. To investigate whether binocular information provides benefits for programming and guidance of reach-to-grasp movements in normal children and whether these eye–hand coordination skills are impaired in children with amblyopia and abnormal binocularity. Methods. Reach-to-grasp performance of the preferred hand in binocular versus monocular (dominant or nondominant eye occluded) conditions to different objects (two sizes, three locations, and two to three repetitions) was quantified by using a 3D motion-capture system. The participants were 36 children (age, 5–11 years) and 11 adults who were normally sighted and 21 children (age, 4–8 years) who had strabismus and/or anisometropia. Movement kinematics and error rates were compared for each viewing condition within and between subject groups. Results. The youngest control subjects used a mainly programmed (ballistic) strategy and collided with the objects more often when viewing with only one eye, while older children progressively incorporated visual feedback to guide their reach and, eventually, their grasp, resulting in binocular advantages for both movement components resembling those of adult performance. Amblyopic children were the worst performers under all viewing conditions, even when using the dominant eye. They spent almost twice as long in the final approach to the objects and made many (1.5–3 times) more errors in reach direction and grip positioning than their normal counterparts, these impairments being most marked in those with the poorest binocularity, regardless of the severity or cause of their amblyopia. Conclusions. The importance of binocular vision for eye–hand coordination normally increases with age and use of online movement guidance. Restoring binocularity in children with amblyopia may improve their poor hand action control. PMID:21212188

  3. Decoupling eye and hand movement control: visual short-term memory influences reach planning more than saccade planning.

    PubMed

    Issen, Laurel A; Knill, David C

    2012-01-04

    When reaching for objects, humans make saccades to fixate the object at or near the time the hand begins to move. In order to address whether the CNS relies on a common representation of target positions to plan both saccades and hand movements, we quantified the contributions of visual short-term memory (VSTM) to hand and eye movements executed during the same coordinated actions. Subjects performed a sequential movement task in which they picked up one of two objects on the right side of a virtual display (the "weapon"), moved it to the left side of the display (to a "reloading station") and then moved it back to the right side to hit the other object (the target). On some trials, the target was perturbed by 1° of visual angle while subjects moved the weapon to the reloading station. Although subjects did not notice the change, the original position of the target, encoded in VSTM, influenced the motor plans for both the hand and the eye back to the target. Memory influenced motor plans for distant targets more than for near targets, indicating that sensorimotor planning is sensitive to the reliability of available information; however, memory had a larger influence on hand movements than on eye movements. This suggests that spatial planning for coordinated saccades and hand movements are dissociated at the level of processing at which online visual information is integrated with information in short-term memory.

  4. Automated cross-modal mapping in robotic eye/hand systems using plastic radial basis function networks

    NASA Astrophysics Data System (ADS)

    Meng, Qinggang; Lee, M. H.

    2007-03-01

    Advanced autonomous artificial systems will need incremental learning and adaptive abilities similar to those seen in humans. Knowledge from biology, psychology and neuroscience is now inspiring new approaches for systems that have sensory-motor capabilities and operate in complex environments. Eye/hand coordination is an important cross-modal cognitive function, and is also typical of many of the other coordinations that must be involved in the control and operation of embodied intelligent systems. This paper examines a biologically inspired approach for incrementally constructing compact mapping networks for eye/hand coordination. We present a simplified node-decoupled extended Kalman filter for radial basis function networks, and compare this with other learning algorithms. An experimental system consisting of a robot arm and a pan-and-tilt head with a colour camera is used to produce results and test the algorithms in this paper. We also present three approaches for adapting to structural changes during eye/hand coordination tasks, and the robustness of the algorithms under noise are investigated. The learning and adaptation approaches in this paper have similarities with current ideas about neural growth in the brains of humans and animals during tool-use, and infants during early cognitive development.

  5. Eye-hand interactions differ in the human premotor and parietal cortices.

    PubMed

    van Donkelaar, Paul; Lee, Ji-Hang; Drew, Anthony S

    2002-09-01

    In order to successfully look at and reach for a visual target the central nervous system must perform a complex sensorimotor transformation. How this transformation is mapped onto relevant brain structures has become the subject of much recent investigation. In the present paper we examined the contribution of the human premotor cortex (PMC) to this transformation process during a task requiring coordinated eye and hand movements. For this purpose, we made use of single-pulse transcranial magnetic stimulation (TMS) to temporarily disrupt the processing occurring in the PMC during task performance. Subjects made open-loop pointing movements accompanied by saccades of the same size or two or three times larger. Under normal circumstances without TMS, the pointing movement amplitude increased with saccade amplitude. When TMS was applied over the PMC 100-200 ms after target presentation, the influence of saccade amplitude on the pointing movement amplitude was increased. This is the opposite effect to that observed in a previous study [Journal of Neurophysiology 84 (200) 1677-1680] when TMS was applied over the posterior parietal cortex (PPC) during the same task. We suggest that this pattern of results is consistent with the coding of the reach plan in eye-centered coordinates in the PPC and limb-centered coordinates in the PMC. Copyright 2002 Elsevier Science B.V.

  6. Hand Function in Multiple Sclerosis: Force Coordination in Manipulation Tasks

    PubMed Central

    Krishnan, Vennila; Jaric, Slobodan

    2008-01-01

    Objective To evaluate the methodology for exploring the specific aspects of functional impairment in multiple sclerosis (MS) through the pattern of forces exerted in various manipulation tasks. Methods Twelve mildly involved MS patients (EDSS 2.5–5.5) and 12 healthy controls performed various static and dynamic manipulation tasks with an instrumented device that recorded the grip (G; normal to the digit device contact area) and load force (L; tangential force that causes lifting). Results MS patients consistently displayed lower indices of task performance (as assessed by the ability to produce the required L profiles) and force coordination (as assessed by G/L ratio, coupling of G and L, and G modulation) than the healthy controls across all tested tasks. Conclusions The applied methodology could be sensitive enough to detect the hand dysfunction in mildly involved individuals with MS. Particularly recommended for future evaluations of the impairment of hand function could be a simple lifting task and the static task of tracing a gradually changing L, as well as the variables depicting both the task performance and G/L ratio. Significance The applied methodology could be developed into a standard clinical test for the assessment of hand function in MS and, possibly, in other neurological diseases. PMID:18760664

  7. Hand function in multiple sclerosis: force coordination in manipulation tasks.

    PubMed

    Krishnan, Vennila; Jaric, Slobodan

    2008-10-01

    To evaluate the methodology for exploring the specific aspects of functional impairment in multiple sclerosis (MS) through the pattern of forces exerted in various manipulation tasks. Twelve mildly involved MS patients (EDSS 2.5-5.5) and 12 healthy controls performed various static and dynamic manipulation tasks with an instrumented device that recorded the grip (G; normal to the digit device contact area) and load force (L; tangential force that causes lifting). MS patients consistently displayed lower indices of task performance (as assessed by the ability to produce the required L profiles) and force coordination (as assessed by G/L ratio, coupling of G and L, and G modulation) than the healthy controls across all tested tasks. The applied methodology could be sensitive enough to detect the hand dysfunction in mildly involved individuals with MS. Particularly recommended for future evaluations of the impairment of hand function could be a simple lifting task and the static task of tracing a gradually changing L, as well as the variables depicting both the task performance and G/L ratio. The applied methodology could be developed into a standard clinical test for the assessment of hand function in MS and, possibly, in other neurological diseases.

  8. Autonomous robot calibration for hand-eye coordination

    SciTech Connect

    Bennett, D.J.; Geiger, D. ); Hollerbach, J.M. )

    1991-10-01

    Autonomous robot calibration is defined as the process of determining a robot's model by using only its internal sensors. It is shown that autonomous calibration of a manipulator and stereo camera system is possible. The proposed autonomous calibration algorithm may obtain the manipulator kinematic parameters, external kinematic camera parameters, and internal camera parameters. To do this, only joint angle readings and camera image plane data are used. A condition for the identifiability of the manipulator/camera parameters is derived. The method is a generalization of a recently developed scheme for self-calibrating a manipulator by forming it into a mobile closed-loop kinematic chain.

  9. Binocular co-ordination of human horizontal saccadic eye movements.

    PubMed Central

    Collewijn, H; Erkelens, C J; Steinman, R M

    1988-01-01

    1. The binocular co-ordination of human horizontal saccades was analysed for the first time systematically over the full oculomotor range with a precise and accurate scleral sensor coil technique. Effects of amplitude (1.25-80 deg), direction (adduction vs. abduction and centrifugal vs. centripetal) and eccentricity (symmetrical about primary or between primary and secondary positions) were systematically investigated in three subjects). 2. To minimize extraneous effects of stimulus presentation on the programming of saccades, subjects were instructed to voluntarily change their gaze between two continuously visible targets. These were positioned on an iso-vergence locus, and thus contained no stimulus for disjunctive eye movements. 3. Under these conditions the amplitudes of the primary saccades of the two eyes were remarkably accurate; undershooting of the target by about 0.5 deg (independent of amplitude in the range 10-70 deg) was typical. This finding contrasts with the undershooting by about 10% described in the literature as characteristic for other stimulus conditions. 4. Saccadic peak velocities saturated at a mean asymptotic level of 502 +/- 32 (S.D.) deg/s for saccades of 40 deg and larger. The duration was linearly related to amplitude for saccades up to 50 deg; for saccades of larger sizes the duration increased progressively more steeply. Skewness values (acceleration time as a fraction of total saccadic duration) decreased from about 0.45 for saccades up to 10 deg to about 0.20 for saccades of 50 deg and larger. 5. Binocular saccades showed an abduction-adduction asymmetry and were not well yoked dynamically. The saccades of the abducting eye consistently had a larger size, a higher peak velocity, a shorter duration and were more skewed than the concomitant adducting saccades of the fellow eye. As a result, the eyes diverged transiently by as much as 3 deg during horizontal saccades. 6. Saccades also showed a marked centrifugal-centripetal asymmetry

  10. Age-related changes in head and eye coordination.

    PubMed

    Proudlock, Frank A; Shekhar, Himanshu; Gottlob, Irene

    2004-01-01

    The effect of ageing upon head movements during gaze shifts is unknown. We have investigated age-related changes in head and eye coordination in a group of healthy volunteers. Horizontal head and eye movements were recorded in 53 subjects, aged between 20 and 83 years, during the performance of saccades, antisaccades, smooth pursuit and a reading task. The subjects were divided into three groups, young subjects (20-40 years), middle-aged subjects (41-60 years) and older subjects (over 60 years). Logarithmic transformations of the head gain were significantly greater in the older subjects compared to the young subjects during the saccadic task (P=0.001), antisaccadic task (P=0.004), smooth pursuit at 20 degrees/s (P=0.001) and 40 degrees/s (P=0.005), but not reading. For saccadic and antisaccadic tasks, the increase in transformed head gain was non-linear with significant differences between older and middle-aged subjects but not middle-aged and young subjects. Head movement tendencies were highly consistent for related tasks. Head movement gain during gaze shifts significantly increases with age, which may contribute to dizziness and balance problems experienced by the elderly.

  11. The Intersection between Ocular and Manual Motor Control: Eye–Hand Coordination in Acquired Brain Injury

    PubMed Central

    Rizzo, John-Ross; Hosseini, Maryam; Wong, Eric A.; Mackey, Wayne E.; Fung, James K.; Ahdoot, Edmond; Rucker, Janet C.; Raghavan, Preeti; Landy, Michael S.; Hudson, Todd E.

    2017-01-01

    Acute and chronic disease processes that lead to cerebral injury can often be clinically challenging diagnostically, prognostically, and therapeutically. Neurodegenerative processes are one such elusive diagnostic group, given their often diffuse and indolent nature, creating difficulties in pinpointing specific structural abnormalities that relate to functional limitations. A number of studies in recent years have focused on eye–hand coordination (EHC) in the setting of acquired brain injury (ABI), highlighting the important set of interconnected functions of the eye and hand and their relevance in neurological conditions. These experiments, which have concentrated on focal lesion-based models, have significantly improved our understanding of neurophysiology and underscored the sensitivity of biomarkers in acute and chronic neurological disease processes, especially when such biomarkers are combined synergistically. To better understand EHC and its connection with ABI, there is a need to clarify its definition and to delineate its neuroanatomical and computational underpinnings. Successful EHC relies on the complex feedback- and prediction-mediated relationship between the visual, ocular motor, and manual motor systems and takes advantage of finely orchestrated synergies between these systems in both the spatial and temporal domains. Interactions of this type are representative of functional sensorimotor control, and their disruption constitutes one of the most frequent deficits secondary to brain injury. The present review describes the visually mediated planning and control of eye movements, hand movements, and their coordination, with a particular focus on deficits that occur following neurovascular, neurotraumatic, and neurodegenerative conditions. Following this review, we also discuss potential future research directions, highlighting objective EHC as a sensitive biomarker complement within acute and chronic neurological disease processes. PMID:28620341

  12. Parameterizations for reducing camera reprojection error for robot-world hand-eye calibration

    USDA-ARS?s Scientific Manuscript database

    Accurate robot-world, hand-eye calibration is crucial to automation tasks. In this paper, we discuss the robot-world, hand-eye calibration problem which has been modeled as the linear relationship AX equals ZB, where X and Z are the unknown calibration matrices composed of rotation and translation ...

  13. Hand and eye preference and their association with task approach by preschoolers.

    PubMed

    Mahone, E Mark; Wodka, Ericka L; Hiemenz, Jennifer R

    2006-06-01

    Hand preference, eye preference, and the concordance of hand-eye preference were assessed in 99 healthy preschool-age children (46 boys: Mage= 55.4 mo., SD= 10.5 and 53 girls: Mage=53.6 mo., SD= 11.8). Children were also administered neuropsychological measures requiring attention and reaching to both sides of midline including the Peabody Picture Vocabulary Test, Third Edition, Multiple Boxes Test, Developmental Neuropsychological Assessment Visual Attention, and Imitating Hand Positions. All groups performed in the average range using standard administration and scoring of the neuropsychological tests, and no significant differences were found in performance between those with left- versus right-hand preference, left-versus right-eye preference, or concordant versus discordant hand/eye preference. In contrast, significant differences were noted in task approach to neuropsychological measures depending on hand preference. Rate of left-hand preference in this sample was consistent with that seen for adults; and rate of left-eye preference, and hand/eye concordance remained stable across age groups 3 to 6 years. While the presence of left-hand or -eye preference or discordance in the preschool years appears to be a benign characteristic in relation to standardized test performance, some aspects of test-taking efficiency may be affected.

  14. Corticospinal Excitability in the Hand Muscles is Decreased During Eye Movement with Visual Occlusion.

    PubMed

    Chujo, Yuta; Jono, Yasutomo; Tani, Keisuke; Nomura, Yoshifumi; Hiraoka, Koichi

    2016-02-01

    Corticospinal excitability in the hand muscles decreases during smooth pursuit eye movement. The present study tested a hypothesis that the decrease in corticospinal excitability in the hand muscles at rest during eye movement is not caused by visual feedback but caused by motor commands to the eye muscles. Healthy men (M age = 28.4 yr., SD = 5.2) moved their eyes to the right with visual occlusion (dark goggles) while their arms and hands remained at rest. The motor-evoked potential in the hand muscles was suppressed by 19% in the third quarter of the eye-movement period, supporting a view that motor commands to the eye muscles are the cause of the decrease in corticospinal excitability in the hand muscles. The amount of the suppression was not significantly different among the muscles, indicating that modulation of corticospinal excitability in one muscle induced by eye movement is not dependent on whether eye movement direction and the direction of finger movement when the muscle contracts are identical. Thus, the finding failed to support a hypothetical view that motor commands to the eye muscles concomittantly produce motor commands to the hand muscles. Moreover, the amount of the suppression was not significantly different between the forearm positions, indicating that the suppression was not affected by proprioception of the forearm muscles when visual feedback is absent. © The Author(s) 2016.

  15. Correlation between hand preference and distance of focusing points of two eyes in the horizontal plane.

    PubMed

    Dane, Senol; Gümüştekin, Kenan

    2002-10-01

    Relationships among hand preference, ocular dominance, and the degree of ocular shifting were studied in 78 right-handed and 16 left-handed subjects. Ocular dominance was assessed with the Miles test. The shifting degree of eye was assessed using a modified Miles test. The shifting distance of the right-eye was marginally greater, although significant, in the left-handers as compared to the right-handers. The shifting distance of the left-eye was greater in the right-handers than in the left-handers. The distance of focusing points of two eyes in the horizontal plane was greater in the right-handers than in the left-handers. In the total sample, there was a significant negative Pearson correlation between hand-preference and the shifting distance of the right-eye, and there was a positive correlation between hand-preference and the shifting distance of the left-eye. In addition, there was a significant positive correlation between hand preference and the distance of focusing points of two eyes. These results suggest that hand preference may be related to the degree of ocular asymmetry.

  16. Development of hand-eye dominance in relation to verbal self-regulation of motor behavior.

    PubMed

    Nagae, S

    1983-01-01

    The development of the relation between hand-eye dominance and verbal self-control of motor behavior was examined with 4- and 5-year-olds. Performances of subjects falling into either crossed or consistent hand-eye dominance categories were compared on a two-choice button-pushing task. Children performed this with their dominant hand in one of two conditions: verbalizing and not verbalizing their button-pushing activity. Results showed that crossed hand-eye dominant children gave significantly poorer performances than consistent hand-eye dominant children and that the former used their self-instructions in a motoric manner. These findings were interpreted as supporting the view that the functions of cerebral hemispheres in children with crossed dominance are more immature than those in children with consistent dominance.

  17. Coordination of gaze and hand movements for tracking and tracing in 3D.

    PubMed

    Gielen, Constantinus C A M; Dijkstra, Tjeerd M H; Roozen, Irene J; Welten, Joke

    2009-03-01

    In this study we have investigated movements in three-dimensional space. Since most studies have investigated planar movements (like ellipses, cloverleaf shapes and "figure eights") we have compared two generalizations of the two-thirds power law to three dimensions. In particular we have tested whether the two-thirds power law could be best described by tangential velocity and curvature in a plane (compatible with the idea of planar segmentation) or whether tangential velocity and curvature should be calculated in three dimensions. We defined total curvature in three dimensions as the square root of the sum of curvature squared and torsion squared. The results demonstrate that most of the variance is explained by tangential velocity and total curvature. This indicates that all three orthogonal components of movements in 3D are equally important and that movements are truly 3D and do not reflect a concatenation of 2D planar movement segments. In addition, we have studied the coordination of eye and hand movements in 3D by measuring binocular eye movements while subjects move the finger along a curved path. The results show that the directional component and finger position almost superimpose when subjects track a target moving in 3D. However, the vergence component of gaze leads finger position by about 250msec. For drawing (tracing) the path of a visible 3D shape, the directional component of gaze leads finger position by about 225msec, and the vergence component leads finger position by about 400msec. These results are compatible with the idea that gaze leads hand position during drawing movement to assist prediction and planning of hand position in 3D space.

  18. Hand-eye dominance in a population with mental handicaps: prevalence and a comparison of methods.

    PubMed

    Robison, S E; Block, S S; Boudreaux, J D; Flora, R J

    1999-09-01

    The primary purpose of this study was to investigate hand-eye dominance in a population with mental handicaps and how the distribution compared with the general population. In addition, this study investigated the correlation between two methods of hand-eye dominance testing. Two methods were used to determine eye dominance: the hole-in-the-hand method and the eye dominance wand. Hand dominance was determined by the subject's choice of accepting hand. The sample was comprised of a population of 421 athletes participating in the 1997 Special Olympic Games in Toronto. All subjects unable to give a dominant hand or unable to perform either of the ocular dominance tests were eliminated from analysis. Athletes who demonstrated strabismus or a difference in visual acuity between the two eyes of greater than 1 line were separated in the analysis, reducing the sample population to 191. The hole-in-the-hand method of eye dominance showed that 40.3% of this population exhibited crossed dominance. The eye dominance wand found crossed dominance in 36.6% of this population. The eye dominance wand demonstrated moderate agreement with the hole-in-the-hand method; however, there was some crossover of eye dominance between tests, when the tests were compared on a case-by-case basis. The prevalence rate of this population of persons with mental handicaps agrees with the prevalence rates found by Robison et al., in which 41% of a general nonhandicapped population demonstrated crossed dominance. The results suggest that persons with mental handicaps have prevalence rates of crossed dominance similar to those found in the general population.

  19. Biomechanical Characteristics of Hand Coordination in Grasping Activities of Daily Living.

    PubMed

    Liu, Ming-Jin; Xiong, Cai-Hua; Xiong, Le; Huang, Xiao-Lin

    2016-01-01

    Hand coordination can allow humans to have dexterous control with many degrees of freedom to perform various tasks in daily living. An important contributing factor to this important ability is the complex biomechanical architecture of the human hand. However, drawing a clear functional link between biomechanical architecture and hand coordination is challenging. It is not understood which biomechanical characteristics are responsible for hand coordination and what specific effect each biomechanical characteristic has. To explore this link, we first inspected the characteristics of hand coordination during daily tasks through a statistical analysis of the kinematic data, which were collected from thirty right-handed subjects during a multitude of grasping tasks. Then, the functional link between biomechanical architecture and hand coordination was drawn by establishing the clear corresponding causality between the tendinous connective characteristics of the human hand and the coordinated characteristics during daily grasping activities. The explicit functional link indicates that the biomechanical characteristic of tendinous connective architecture between muscles and articulations is the proper design by the Creator to perform a multitude of daily tasks in a comfortable way. The clear link between the structure and the function of the human hand also suggests that the design of a multifunctional robotic hand should be able to better imitate such basic architecture.

  20. Biomechanical Characteristics of Hand Coordination in Grasping Activities of Daily Living

    PubMed Central

    Liu, Ming-Jin; Xiong, Cai-Hua; Xiong, Le; Huang, Xiao-Lin

    2016-01-01

    Hand coordination can allow humans to have dexterous control with many degrees of freedom to perform various tasks in daily living. An important contributing factor to this important ability is the complex biomechanical architecture of the human hand. However, drawing a clear functional link between biomechanical architecture and hand coordination is challenging. It is not understood which biomechanical characteristics are responsible for hand coordination and what specific effect each biomechanical characteristic has. To explore this link, we first inspected the characteristics of hand coordination during daily tasks through a statistical analysis of the kinematic data, which were collected from thirty right-handed subjects during a multitude of grasping tasks. Then, the functional link between biomechanical architecture and hand coordination was drawn by establishing the clear corresponding causality between the tendinous connective characteristics of the human hand and the coordinated characteristics during daily grasping activities. The explicit functional link indicates that the biomechanical characteristic of tendinous connective architecture between muscles and articulations is the proper design by the Creator to perform a multitude of daily tasks in a comfortable way. The clear link between the structure and the function of the human hand also suggests that the design of a multifunctional robotic hand should be able to better imitate such basic architecture. PMID:26730579

  1. The eye contact effect in request and emblematic hand gestures.

    PubMed

    Ferri, Francesca; Busiello, Marianna; Campione, Giovanna C; De Stefani, Elisa; Innocenti, Alessandro; Romani, Gian Luca; Costantini, Marcello; Gentilucci, Maurizio

    2014-03-01

    Request and emblematic gestures, despite being both communicative gestures, do differ in terms of social valence. Indeed, only the former are used to initiate/maintain/terminate an actual interaction. If such a difference is at stake, a relevant social cue, i.e. eye contact, should have different impacts on the neuronal underpinnings of the two types of gesture. We measured blood oxygen level-dependent signals, using functional magnetic resonance imaging, while participants watched videos of an actor, either blindfolded or not, performing emblems, request gestures, or meaningless control movements. A left-lateralized network was more activated by both types of communicative gestures than by meaningless movements, regardless of the accessibility of the actor's eyes. Strikingly, when eye contact was taken into account as a factor, a right-lateralized network was more strongly activated by emblematic gestures performed by the non-blindfolded actor than by those performed by the blindfolded actor. Such modulation possibly reflects the integration of information conveyed by the eyes with the representation of emblems. Conversely, a wider right-lateralized network was more strongly activated by request gestures performed by the blindfolded than by those performed by the non-blindfolded actor. This probably reflects the effect of the conflict between the observed action and its associated contextual information, in which relevant social cues are missing. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  2. Effects of an Occupational Therapy Hand Dominance Transfer Intervention for Soldiers With Crossed Hand-Eye Dominance.

    PubMed

    Luken, Michelle; Yancosek, Kathleen E

    2017-01-01

    Crossed dominance (CD) is defined as an individual's dominant hand and dominant eye being on opposite sides of the body. CD negatively impacts an individual's ability to accurately aim and fire long-barreled guns. The authors developed and evaluated a hand dominance transfer (HDT) intervention to improve the M16 rifle shooting accuracy, efficiency, and skill transfer. Twenty-four U.S. Army soldiers with CD were taught how to handle and fire an M16 rifle using the nondominant hand. Training was conducted at a military, indoor laser-equipped weapons simulator. Accuracy for shooting 40 rounds at baseline with the nondominant eye and dominant hand (NDE/DH) was 22.12 compared to shooting 30.46 with the dominant eye and nondominant hand (DE/NDH). This difference was statistically significant with p = .000. The transfer of shooting accuracy skill (retention) following the HDT intervention was 33.42 with a comparative p value of .100. Efficiency of shooting 10 rounds at baseline with the NDE/DH was 6.3 compared to shooting 7.3 with the DE/NDH. This difference was not statistically significant (p = .107). The transfer of shooting efficiency skill (retention) was 7.96 with a comparative p value of .349. This study supports shooting with the DE/NDH. HDT could be further developed to address the soldiering skill of shooting an M16.

  3. Eye-head coordination during large gaze shifts.

    PubMed

    Tweed, D; Glenn, B; Vilis, T

    1995-02-01

    1. Three-dimensional (3D) eye and head rotations were measured with the use of the magnetic search coil technique in six healthy human subjects as they made large gaze shifts. The aims of this study were 1) to see whether the kinematic rules that constrain eye and head orientations to two degrees of freedom between saccades also hold during movements; 2) to chart the curvature and looping in eye and head trajectories; and 3) to assess whether the timing and paths of eye and head movements are more compatible with a single gaze error command driving both movements, or with two different feedback loops. 2. Static orientations of the eye and head relative to space are known to resemble the distribution that would be generated by a Fick gimbal (a horizontal axis moving on a fixed vertical axis). We show that gaze point trajectories during eye-head gaze shifts fit the Fick gimbal pattern, with horizontal movements following straight "line of latitude" paths and vertical movements curving like lines of longitude. However, horizontal (and to a lesser extent vertical) movements showed direction-dependent looping, with rightward and leftward (and up and down) saccades tracing slightly different paths. Plots of facing direction (the analogue of gaze direction for the head) also showed the latitude/longitude pattern, without looping. In radial saccades, the gaze point initially moved more vertically than the target direction and then curved; head trajectories were straight. 3. The eye and head components of randomly sequenced gaze shifts were not time locked to one another. The head could start moving at any time from slightly before the eye until 200 ms after, and the standard deviation of this interval could be as large as 80 ms. The head continued moving for a long (up to 400 ms) and highly variable time after the gaze error had fallen to zero. For repeated saccades between the same targets, peak eye and head velocities were directly, but very weakly, correlated; fast eye

  4. Dynamic assessment of binocular eye movement coordination: norms and functional implications.

    PubMed

    Viirre, Erik

    2014-01-01

    Alignment of the two eyes is controlled by a finely tuned, fast acting system with components within the brain. Assessment of binocular alignment has classically been done statically. Eye positions are assessed in primary position and at eccentric angles to interpret the functional status of the oculomotor nerves and muscles. However, assessment of dynamic eye alignment, the coordination of the eyes during eye movements, has been less commonly carried out and has not been formalized with population norms. Clinicians are aware of slow eye movement dynamic alignment changes, such as that clinically observed in Intranuclear Ophthalmoplegia. But assessment of eye alignment during rapid eye movements, such as saccade or pursuit has not been part of neuro-ophthalmologic assessment. With the advent of inexpensive, high resolution recording systems, both eyes can be simultaneously recorded and their coordination during movement compared. Thus, we now have an opportunity to provide a laboratory based objective measurement of a gamut of binocular coordination systems. Recent research in humans has demonstrated increased variability of binocular coordination during divided attention. Variability is an interesting statistic that can be sensitively assessed in the velocity domain without extensive gaze position recalibration procedures during recording over long intervals. Variability can thus be used as a robust, long-term eye movement parameter with minimal intrusiveness to the subject. It is proposed that population studies of binocular coordination during eye movements be carried out to determine neurologic norms so that conditions such as brain injury and others can be assessed with a functional tool with objective parameters.

  5. Interaction of hand preference with eye dominance on accuracy in archery.

    PubMed

    Laborde, Sylvain; Dosseville, Fabrice E M; Leconte, Pascale; Margas, Nicolas

    2009-04-01

    In this study, the interaction of hand preference, eye dominance, and performance in archery was investigated. Beginners' accuracy (right-handed French students (48 men, 34 women) from the University of Sport Sciences (M age = 19.3 yr., SD = 1.7 yr.), were tested and 1,323 practitioners were given a laterality questionnaire. Analysis suggested the interaction of hand preference and eye dominance might influence accuracy of the novice archers (uncrossed patterns were more accurate) when the bow was used without sights, but the use of sights by practitioners seemed to eliminate this effect.

  6. Cognitive Control of Saccadic Eye Movements in Children with Developmental Coordination Disorder

    PubMed Central

    Gonzalez, Claudia C.; Mon-Williams, Mark; Burke, Siobhan; Burke, Melanie R.

    2016-01-01

    The ability to use advance information to prepare and execute a movement requires cognitive control of behaviour (e.g., anticipation and inhibition). Our aim was to explore the integrity of saccadic eye movement control in developmental coordination disorder (DCD) and typically developing (TD) children (8–12 years) and assess how these children plan and inhibit saccadic responses, the principal mechanisms within visual attention control. Eye movements and touch responses were measured (separately and concurrently) in Cued and Non-Cued conditions. We found that children with DCD had similar saccade kinematics to the TD group during saccade initiation. Advance information decreased hand movement duration in both groups during Cued trials, but decrements in accuracy were significantly worse in the DCD group. In addition, children with DCD exhibited greater inhibitory errors and inaccurate fixation during the Cued trials. Thus, children with DCD were reasonably proficient in executing saccades during reflexive (Non-Cued) conditions, but showed deficits in more complex control processes involving prediction and inhibition. These findings have implications for our understanding of motor control in children with DCD. PMID:27812128

  7. Cognitive Control of Saccadic Eye Movements in Children with Developmental Coordination Disorder.

    PubMed

    Gonzalez, Claudia C; Mon-Williams, Mark; Burke, Siobhan; Burke, Melanie R

    2016-01-01

    The ability to use advance information to prepare and execute a movement requires cognitive control of behaviour (e.g., anticipation and inhibition). Our aim was to explore the integrity of saccadic eye movement control in developmental coordination disorder (DCD) and typically developing (TD) children (8-12 years) and assess how these children plan and inhibit saccadic responses, the principal mechanisms within visual attention control. Eye movements and touch responses were measured (separately and concurrently) in Cued and Non-Cued conditions. We found that children with DCD had similar saccade kinematics to the TD group during saccade initiation. Advance information decreased hand movement duration in both groups during Cued trials, but decrements in accuracy were significantly worse in the DCD group. In addition, children with DCD exhibited greater inhibitory errors and inaccurate fixation during the Cued trials. Thus, children with DCD were reasonably proficient in executing saccades during reflexive (Non-Cued) conditions, but showed deficits in more complex control processes involving prediction and inhibition. These findings have implications for our understanding of motor control in children with DCD.

  8. Review and Evaluation of Hand-Arm Coordinate Systems for Measuring Vibration Exposure, Biodynamic Responses, and Hand Forces.

    PubMed

    Dong, Ren G; Sinsel, Erik W; Welcome, Daniel E; Warren, Christopher; Xu, Xueyan S; McDowell, Thomas W; Wu, John Z

    2015-09-01

    The hand coordinate systems for measuring vibration exposures and biodynamic responses have been standardized, but they are not actually used in many studies. This contradicts the purpose of the standardization. The objectives of this study were to identify the major sources of this problem, and to help define or identify better coordinate systems for the standardization. This study systematically reviewed the principles and definition methods, and evaluated typical hand coordinate systems. This study confirms that, as accelerometers remain the major technology for vibration measurement, it is reasonable to standardize two types of coordinate systems: a tool-based basicentric (BC) system and an anatomically based biodynamic (BD) system. However, these coordinate systems are not well defined in the current standard. Definition of the standard BC system is confusing, and it can be interpreted differently; as a result, it has been inconsistently applied in various standards and studies. The standard hand BD system is defined using the orientation of the third metacarpal bone. It is neither convenient nor defined based on important biological or biodynamic features. This explains why it is rarely used in practice. To resolve these inconsistencies and deficiencies, we proposed a revised method for defining the realistic handle BC system and an alternative method for defining the hand BD system. A fingertip-based BD system for measuring the principal grip force is also proposed based on an important feature of the grip force confirmed in this study.

  9. Looking at eye dominance from a different angle: is sighting strength related to hand preference?

    PubMed

    Carey, David P; Hutchinson, Claire V

    2013-10-01

    Sighting dominance (the behavioural preference for one eye over the other under monocular viewing conditions) has traditionally been thought of as a robust individual trait. However, Khan and Crawford (2001) have shown that, under certain viewing conditions, eye preference reverses as a function of horizontal gaze angle. Remarkably, the reversal of sighting from one eye to the other depends on which hand is used to reach out and grasp the target. Their procedure provides an ideal way to measure the strength of monocular preference for sighting, which may be related to other indicators of hemispheric specialisation for speech, language and motor function. Therefore, we hypothesised that individuals with consistent side preferences (e.g., right hand, right eye) should have more robust sighting dominance than those with crossed lateral preferences. To test this idea, we compared strength of eye dominance in individuals who are consistently right or left sided for hand and foot preference with those who are not. We also modified their procedure in order to minimise a potential image size confound, suggested by Banks et al. (2004) as an explanation of Khan and Crawford's results. We found that the sighting dominance switch occurred at similar eccentricities when we controlled for effects of hand occlusion and target size differences. We also found that sighting dominance thresholds change predictably with the hand used. However, we found no evidence for relationships between strength of hand preference as assessed by questionnaire or by pegboard performance and strength of sighting dominance. Similarly, participants with consistent hand and foot preferences did not show stronger eye preference as assessed using the Khan and Crawford procedure. These data are discussed in terms of indirect relationships between sighting dominance, hand preference and cerebral specialisation for language and motor control. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Eye-head coordination during optokinetic stimulation in squirrel monkeys

    NASA Technical Reports Server (NTRS)

    Kubo, T.; Igarashi, M.; Jensen, D. W.; Homick, J. L.

    1981-01-01

    Head and eye movements in the yaw plane were recorded during and after optokinetic stimulation in squirrel monkeys. 1) Phasic or tonic head deviations to the side of the ocular quick phase occurred in 94% of total recordings (n = 50) during the perstimulus period, and in 75% of recordings (n = 49) during the poststimulus period. Magnitude of mean head deviation was significantly different between perstimulus and poststimulus periods. 2) Head nystagmus associated with eye nystagmus was consistently observed in seven of nine squirrel monkeys during optokinetic stimulation. Squirrel monkeys are thereby less prone to display head nystagmus than either guinea pigs, pigeons or chickens. 3) Slow phase speeds of coupled head and eye nystagmus were subjected to statistical analysis. A highly significant negative correlation was found between slow phase head and eye speeds. The correlation coefficient was - 0.81 at 60 degrees / sec stimulus (n = 119) and -0.72 at 100 degrees / sec stimulus (n = 131). The gaze speed, calculated by summing the head and eye speeds, was 59.1 plus or minus 6.8 / sec at 60 degrees / sec and 92.2 plus or minus 11.4 at 100 degrees / sec stimulus. There was no significant difference between the gaze speed in a free head condition and the eye speed when the head was fixed.

  11. Eye-head coordination during optokinetic stimulation in squirrel monkeys

    NASA Technical Reports Server (NTRS)

    Kubo, T.; Igarashi, M.; Jensen, D. W.; Homick, J. L.

    1981-01-01

    Head and eye movements in the yaw plane were recorded during and after optokinetic stimulation in squirrel monkeys. 1) Phasic or tonic head deviations to the side of the ocular quick phase occurred in 94% of total recordings (n = 50) during the perstimulus period, and in 75% of recordings (n = 49) during the poststimulus period. Magnitude of mean head deviation was significantly different between perstimulus and poststimulus periods. 2) Head nystagmus associated with eye nystagmus was consistently observed in seven of nine squirrel monkeys during optokinetic stimulation. Squirrel monkeys are thereby less prone to display head nystagmus than either guinea pigs, pigeons or chickens. 3) Slow phase speeds of coupled head and eye nystagmus were subjected to statistical analysis. A highly significant negative correlation was found between slow phase head and eye speeds. The correlation coefficient was - 0.81 at 60 degrees / sec stimulus (n = 119) and -0.72 at 100 degrees / sec stimulus (n = 131). The gaze speed, calculated by summing the head and eye speeds, was 59.1 plus or minus 6.8 / sec at 60 degrees / sec and 92.2 plus or minus 11.4 at 100 degrees / sec stimulus. There was no significant difference between the gaze speed in a free head condition and the eye speed when the head was fixed.

  12. Lateral preferences of hand, eye and foot: relation to cerebral dominance.

    PubMed

    Nachshon, I; Denno, D; Aurand, S

    1983-01-01

    Patterns of lateral preferences of hand, eye and foot were analyzed on 7364 children, differing in race (black and white) and sex. Right hand and foot preferences were found in over 80%, and right eye preferences were found in over 50% of the subjects. No sex or race differences appeared in left-right preferences. However, significantly more females than males, and more blacks than whites, showed variable foot preference. Further analyses of cross preferences indicated that about 40% of the subjects showed consistent lateral preferences of hand, eye, and foot (about 37% right, and about 3% left), whereas the other 60% were divided among ten groups of different preference combinations. The three lateral measures were correlated to differing degrees. The data were interpreted as showing the effects of cerebral dominance on lateral preferences of hand, eye and foot. The effects seemed to be considerably stronger for hand and foot than for eye preferences. Due to a lack of supporting data, interpretation of race differences in variable foot preference must be considered tentative.

  13. Eyes versus hands: How perceived stimuli influence motor actions.

    PubMed

    Geiger, Alexander; Niessen, Eva; Bente, Gary; Vogeley, Kai

    2017-01-01

    Many studies showed that biological (e.g., gaze-shifts or hand movements) and non-biological stimuli (e.g., arrows or moving points) redirect attention. Biological stimuli seem to be more suitable than non-biological to perform this task. However, the question remains if biological stimuli do have different influences on redirecting attention and if this property is dependent on how we react to those stimuli. In two separate experiments, participants interact either with a biological or a non-biological stimulus (experiment 1), or with two biological stimuli (gaze-shifts, hand movements)(experiment 2) to which they responded with two different actions (saccade, button press), either in a congruent or incongruent manner. Results from experiment 1 suggest that interacting with the biological stimulus lead to faster responses, compared to the non-biological stimulus, independent of the response type. Results from experiment 2 show longer reaction times when the depicted stimulus was not matching the response type (e.g., reacting with hand movements to a moving object or gaze-shift) compared to a matching condition, while especially the gaze-following condition (reacting with a gaze shift to a perceived gaze shift) led to the fastest responses. These results suggest that redirecting attention is not only dependent on the perceived stimulus but also on the way how those stimuli are responded to.

  14. Coordinated Genetic Scaling of the Human Eye: Shared Determination of Axial Eye Length and Corneal Curvature

    PubMed Central

    Guggenheim, Jeremy A.; Zhou, Xin; Evans, David M.; Timpson, Nicholas J.; McMahon, George; Kemp, John P.; St Pourcain, Beate; Northstone, Kate; Ring, Susan M.; Fan, Qiao; Wong, Tien-Yin; Cheng, Ching Yu; Khor, Chiea Chuen; Aung, Tin; Saw, Seang Mei; Williams, Cathy

    2013-01-01

    Purpose. To examine the extent to which the two major determinants of refractive error, corneal curvature and axial length, are scaled relative to one another by shared genetic variants, along with their relationship to the genetic scaling of height. Methods. Corneal curvature, axial length, and height were measured in unrelated 14- to 17-year-old white European participants of the Avon Longitudinal Study of Parents and Children (ALSPAC; n = 1915) and in unrelated 40- to 80-year-old participants of the Singapore Chinese Eye Study (SCES; n = 1642). Univariate and bivariate heritability analyses were performed with methods that avoid confounding by common family environment, using information solely from genome-wide high-density genotypes. Results. In ALSPAC subjects, axial length, corneal curvature, and height had similar lower-bound heritability estimates: axial length, h2 = 0.46 (SE = 0.16, P = 0.002); corneal curvature, h2 = 0.42 (SE = 0.16, P = 0.004); height, h2 = 0.48 (SE = 0.17, P = 0.002). The corresponding estimates in the SCES were 0.79 (SE = 0.18, P < 0.001), 0.35 (SE = 0.20, P = 0.036), and 0.31 (SE = 0.20, P = 0.061), respectively. The genetic correlation between corneal curvature and axial length was 0.69 (SE = 0.17, P = 0.019) for ALSPAC participants and 0.64 (SE = 0.22, P = 0.003) for SCES participants. In the subset of 1478 emmetropic ALSPAC individuals, the genetic correlation was 0.85 (SE = 0.12, P = 0.008). Conclusions. These results imply that coordinated scaling of ocular component dimensions is largely achieved by hundreds to thousands of common genetic variants, each with a small pleiotropic effect. Furthermore, genome-wide association studies (GWAS) for either axial length or corneal curvature are likely to identify variants controlling overall eye size when using discovery cohorts dominated by emmetropes, but trait-specific variants in discovery cohorts dominated by ametropes. PMID:23385790

  15. 3-D Object Recognition Using Combined Overhead And Robot Eye-In-Hand Vision System

    NASA Astrophysics Data System (ADS)

    Luc, Ren C.; Lin, Min-Hsiung

    1987-10-01

    A new approach for recognizing 3-D objects using a combined overhead and eye-in-hand vision system is presented. A novel eye-in-hand vision system using a fiber-optic image array is described. The significance of this approach is the fast and accurate recognition of 3-D object information compared to traditional stereo image processing. For the recognition of 3-D objects, the over-head vision system will take 2-D top view image and the eye-in-hand vision system will take side view images orthogonal to the top view image plane. We have developed and demonstrated a unique approach to integrate this 2-D information into a 3-D representation based on a new approach called "3-D Volumetric Descrip-tion from 2-D Orthogonal Projections". The Unimate PUMA 560 and TRAPIX 5500 real-time image processor have been used to test the success of the entire system.

  16. An eye-to-hand magnet effect reveals distinct spatial interference in motor planning and execution.

    PubMed

    Richardson, Brian A; Cluff, Tyler; Lyons, James; Balasubramaniam, Ramesh

    2013-03-01

    An important question in oculomanual control is whether motor planning and execution modulate interference between motion of the eyes and hands. Here we investigated oculomanual interference using a novel paradigm that required saccadic eye movements and unimanual finger tapping. We examined finger trajectories for spatial interference caused by concurrent saccades. The first experiment used synchronous cues so that saccades and taps shared a common timekeeping goal. We found that finger trajectories showed bilateral interference where either finger was attracted in the direction of the accompanying saccade. The second experiment avoided interference due to shared planning resources by examining interference caused by reactive saccades. Here, we observed a lesser degree of execution-dependent coupling where the finger trajectory deviated only when reactive saccades were directed toward the hemifield of the responding hand. Our results show that distinct forms of eye-to-hand coupling emerge according to the demands of the task.

  17. An Eye in the Palm of Your Hand: Alterations in Visual Processing Near the Hand, a Mini-Review

    PubMed Central

    Perry, Carolyn J.; Amarasooriya, Prakash; Fallah, Mazyar

    2016-01-01

    Feedback within the oculomotor system improves visual processing at eye movement end points, also termed a visual grasp. We do not just view the world around us however, we also reach out and grab things with our hands. A growing body of literature suggests that visual processing in near-hand space is altered. The control systems for moving either the eyes or the hands rely on parallel networks of fronto-parietal regions, which have feedback connections to visual areas. Since the oculomotor system effects on visual processing occur through feedback, both through the motor plan and the motor efference copy, a parallel system where reaching and/or grasping motor-related activity also affects visual processing is likely. Areas in the posterior parietal cortex, for example, receive proprioceptive and visual information used to guide actions, as well as motor efference signals. This trio of information channels is all that would be necessary to produce spatial allocation of reach-related visual attention. We review evidence from behavioral and neurophysiological studies that support the hypothesis that feedback from the reaching and/or grasping motor control networks affects visual processing while noting ways in which it differs from that seen within the oculomotor system. We also suggest that object affordances may represent the neural mechanism through which certain object features are selected for preferential processing when stimuli are near the hand. Finally, we summarize the two effector-based feedback systems and discuss how having separate but parallel effector systems allows for efficient decoupling of eye and hand movements. PMID:27148034

  18. Correlation between hand preference and intraocular pressure from right- and left-eyes in right- and left-handers.

    PubMed

    Dane, Senol; Gümüştekin, Kenan; Yazici, Ahmet Taylan; Baykal, Orhan

    2003-02-01

    To test whether there is a relationship between handedness and the intraocular pressure and there is a lateralization in the intraocular pressure, the intraocular pressures of the right- and left-eyes were compared in right- and left-handed students. The intraocular pressures were higher in the right-eye than in the left-eye in men, right-handers, and right-eyed subjects; there was no right-left difference in females, left-handers, left-eyed, and both-eyed subjects. The intraocular pressure of right- and left-eyes was higher in left-handers than right-handers. And there were significant negative correlations between hand preference and the intraocular pressure of both right- and left-eyes. We have concluded that the dominant eye has higher intraocular pressure compared to the nondominant one, and there is a relationship between hand preference and the intraocular pressure.

  19. The Effect of Intensive Bimanual Training on Coordination of the Hands in Children with Congenital Hemiplegia

    ERIC Educational Resources Information Center

    Hung, Ya-Ching; Casertano, Lorenzo; Hillman, Andrew; Gordon, Andrew M.

    2011-01-01

    Recent studies have suggested efficacy of intensive bimanual training in improving the quality and quantity of affected hand use in children with hemiplegia. However, it is not known whether such training affects the coordination of the two hands. In the present study, 20 children with congenital hemiplegia (age 4-10 years; MACS levels I-II) were…

  20. The Effect of Intensive Bimanual Training on Coordination of the Hands in Children with Congenital Hemiplegia

    ERIC Educational Resources Information Center

    Hung, Ya-Ching; Casertano, Lorenzo; Hillman, Andrew; Gordon, Andrew M.

    2011-01-01

    Recent studies have suggested efficacy of intensive bimanual training in improving the quality and quantity of affected hand use in children with hemiplegia. However, it is not known whether such training affects the coordination of the two hands. In the present study, 20 children with congenital hemiplegia (age 4-10 years; MACS levels I-II) were…

  1. Head, eye and arm coordination in table tennis.

    PubMed

    Rodrigues, Sérgio T; Vickers, Joan N; Williams, A Mark

    2002-03-01

    The aim of this study was to determine the role of head, eye and arm movements during the execution of a table tennis forehand stroke. Three-dimensional kinematic analysis of line-of-gaze, arm and ball was used to describe visual and motor behaviour. Skilled and less skilled participants returned the ball to cued right or left target areas under three levels of temporal constraint: pre-, early- and late-cue conditions. In the pre- and early-cue conditions, both high and low skill participants tracked the ball early in flight and kept gaze stable on a location in advance of the ball before ball-bat contact. Skilled participants demonstrated an earlier onset of ball tracking and recorded higher performance accuracy than less skilled counterparts. The manipulation of cue condition showed the limits of adaptation to maintain accuracy on the target. Participants were able to accommodate the constraints imposed by the early-cue condition by using a shorter quiet eye duration, earlier quiet eye offset and reduced arm velocity at contact. In the late-cue condition, modifications to gaze, head and arm movements were not sufficient to preserve accuracy. The findings highlight the functional coupling between perception and action during time-constrained, goal-directed actions.

  2. The effect of intensive bimanual training on coordination of the hands in children with congenital hemiplegia.

    PubMed

    Hung, Ya-Ching; Casertano, Lorenzo; Hillman, Andrew; Gordon, Andrew M

    2011-01-01

    Recent studies have suggested efficacy of intensive bimanual training in improving the quality and quantity of affected hand use in children with hemiplegia. However, it is not known whether such training affects the coordination of the two hands. In the present study, 20 children with congenital hemiplegia (age 4-10 years; MACS levels I-II) were randomly assigned to either an intensive bimanual training (Hand-Arm Bimanual Intensive Therapy: HABIT) group, or a control group consisting of equally intensive unimanual treatment (Constraint-Induced Movement Therapy, CIMT) for 6h per day for 15 days (90h). To assess their bimanual coordination, children were asked to open a drawer with one hand and manipulate its contents with the other hand. 3-D movement kinematics were recorded and subsequently analyzed by a blind evaluator. The role of the two hands was varied. Following treatment, superior improvement in bimanual coordination was found for the bimanual training group as indicated by greater movement overlap (the percentage of time with both hands engaged in the task p = 0.047) and better goal synchronization (reduced time differences between the two hands completing the task goals, p = 0.005). The results suggest that bimanual training improves the spatial-temporal control of the two hands, and are in agreement with the principle of practice specificity. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. The Effect of Eye Fatigue on Reading, Based on Test Scores and the Presence of Deviant Eye Coordination, Either Esophoria, Exophoria or Hyperphoria.

    ERIC Educational Resources Information Center

    Gillis, George A.

    Studied were eye coordination and effects of fatigue on vision in the visual and academic functioning of 1049 students in grades 1 through 10. An earlier study (1966) examined the eye coordination of 1152 students in grades 1 through 12. The common Snellen Test of Visual Acuity failed to indicate 42% of students who were diagnosed by other tests…

  4. Assessment of hand function through the coordination of contact forces in manipulation tasks.

    PubMed

    Jaric, Slobodan; Uygur, Mehmet

    2013-03-01

    Exploration of force coordination has been one of the most often used approaches in studies of hand function. When holding and manipulating a hand-held object healthy individuals are typically able to highly coordinate the perpendicular (grip force; GF) with the tangential component of the contact force (load force; LF). The purpose of this review is to present the findings of our recent studies of GF-LF coordination. Regarding the mechanical factors affecting GF-LF coordination, our data suggest that both different hand segments and their particular skin areas could have markedly different friction properties. It also appears that the absolute, rather than relative safety margin (i.e., how much the actual GF exceeds the minimum value that prevents slipping) should be a variable of choice when assessing the applied magnitude of GF. The safety margin could also be lower in static than in free holding tasks. Regarding the involved neural factors, the data suggest that the increased frequency, rather than an increased range of a cyclic LF could have a prominent detrimental effect on the GF-LF coordination. Finally, it appears that the given instructions (e.g., 'to hold' vs. 'to pull') can prominently alter GF-LF coordination in otherwise identical manipulation tasks. Conversely, the effects of handedness could be relatively week showing only slight lagging of GF in the non-dominant, but not in the dominant hand. The presented findings reveal important aspects of hand function as seen through GF-LF coordination. Specifically, the use of specific hand areas for grasping, calculation of particular safety margins, the role of LF frequency (but not of LF range) and the effects of given instructions should be all taken into account when conducting future studies of manipulation tasks, standardizing their procedures and designing routine clinical tests of hand function.

  5. Image-Based Visual Tracking Control of Hand-Eye Robot for Moving Target Object

    NASA Astrophysics Data System (ADS)

    Ito, Masahide; Shibata, Masaaki

    In this paper, we propose an image-based visual tracking control method of a hand-eye robot for a moving target object. The hand-eye robot is constructed from a three-DoF planar manipulator and a single CCD camera that is mounted on the end-effector. This robot is a typical example of an eye-in-hand system with a single camera. The control objective is to keep the target object around the center of the image plane. In many conventional visual servo methods, it is assumed that the target object is static. Consequently, the visual tracking delay arises in the case of a moving target object. Although we have already proposed a non-delayed visual tracking control method for a moving target object, this method is developed only for a stereo vision robot with two CCD cameras. Therefore, this paper provides such a visual tracking control method for the hand-eye robot. The validity of our control method is evaluated by an experiment.

  6. The hand sees visual periphery better than the eye: motor-dependent visual motion analyses.

    PubMed

    Gomi, Hiroaki; Abekawa, Naotoshi; Shimojo, Shinsuke

    2013-10-16

    Information pertaining to visual motion is used in the brain not only for conscious perception but also for various kinds of motor controls. In contrast to the increasing amount of evidence supporting the dissociation of visual processing for action versus perception, it is less clear whether the analysis of visual input is shared for characterizing various motor outputs, which require different kinds of interactions with environments. Here we show that, in human visuomotor control, motion analysis for quick hand control is distinct from that for quick eye control in terms of spatiotemporal analysis and spatial integration. The amplitudes of implicit and quick hand and eye responses induced by visual motion stimuli differently varied with stimulus size and pattern smoothness (e.g., spatial frequency). Surprisingly, the hand response did not decrease even when the visual motion with a coarse pattern was mostly occluded over the visual center, whereas the eye response markedly decreased. Since these contrasts cannot be ascribed to any difference in motor dynamics, they clearly indicate different spatial integration of visual motion for the individual motor systems. Going against the overly unified hierarchical view of visual analysis, our data suggest that visual motion analyses are separately tailored from early levels to individual motor modalities. Namely, the hand and eyes see the external world differently.

  7. Eye and Hand Dominance in Kindergarten and First-Grade Children

    ERIC Educational Resources Information Center

    Van Camp, Sarah S.; Bixby, Matilda B.

    1977-01-01

    This study attempted to gather baseline data on a randomly selected population of 353 kindergarten and first-grade children for consistency of response in hand dominance measures and eye dominance measures and for comparison by sex, race, maturity and socioeconomic status. (Author/SB)

  8. Head-Torso-Hand Coordination in Children with and without Developmental Coordination Disorder

    ERIC Educational Resources Information Center

    Elders, Vera; Sheehan, Sinead; Wilson, Andrew D.; Levesley, Martin; Bhakta, Bipin; Mon-Williams, Mark

    2010-01-01

    Aim: This study investigated the nature of coordination and control problems in children with developmental coordination disorder (DCD). Method: Seven adults (two males, five females, age range 20-28y; mean 23y, SD 2y 8mo) and eight children with DCD (six males, two females, age range 7-9y; mean 8y, SD 8mo), and 10 without DCD (seven males, three…

  9. Head-Torso-Hand Coordination in Children with and without Developmental Coordination Disorder

    ERIC Educational Resources Information Center

    Elders, Vera; Sheehan, Sinead; Wilson, Andrew D.; Levesley, Martin; Bhakta, Bipin; Mon-Williams, Mark

    2010-01-01

    Aim: This study investigated the nature of coordination and control problems in children with developmental coordination disorder (DCD). Method: Seven adults (two males, five females, age range 20-28y; mean 23y, SD 2y 8mo) and eight children with DCD (six males, two females, age range 7-9y; mean 8y, SD 8mo), and 10 without DCD (seven males, three…

  10. Eye movements show similar adaptations in temporal coordination to movement planning conditions in both people with and without cerebral palsy.

    PubMed

    Payne, Alexander R; Plimmer, Beryl; McDaid, Andrew; Davies, T Claire

    2017-05-01

    The effects of cerebral palsy on movement planning for simple reaching tasks are not well understood. Movement planning is complex and entails many processes which could be affected. This study specifically sought to evaluate integrating task information, decoupling movements, and adjusting to altered mapping. For a reaching task, the asynchrony between the eye onset and the hand onset was measured across different movement planning conditions for participants with and without cerebral palsy. Previous research shows people without cerebral palsy vary this temporal coordination for different planning conditions. Our measurements show similar adaptations in temporal coordination for groups with and without cerebral palsy, to three of the four variations in planning condition tested. However, movement durations were still longer for the participants with cerebral palsy. Hence for simple goal-directed reaching, movement execution problems appear to limit activity more than movement planning deficits.

  11. Self-moved target eye tracking in control and deafferented subjects: roles of arm motor command and proprioception in arm-eye coordination.

    PubMed

    Vercher, J L; Gauthier, G M; Guédon, O; Blouin, J; Cole, J; Lamarre, Y

    1996-08-01

    1. When a visual target is moved by the subject's hand (self-moved target tracking), smooth pursuit (SP) characteristics differ from eye-alone tracking: SP latency is shorter and maximal eye velocity is higher in self-moved target tracking than in eye-alone tracking. The aim of this study was to determine which signals (motor command and/or proprioception) generated during arm motion are responsible for the decreased time interval between arm and eye motion onsets in self-moved target tracking. 2. Six control subjects tracked a visual target whose motion was generated by active or passive movements of the observer's arm in order to determine the role played by arm proprioception in the arm-eye coordination. In a second experiment, the participation of two subjects suffering complete loss of proprioception allowed us to assess the contribution of arm motor command signals. 3. In control subjects, passive movement of the arm led to eye latencies significantly longer (130 ms) than when the arm was actively self-moved (-5 ms:negative values meaning that the eyes actually started to move before the target) but slightly shorter than in eye-alone tracking (150 ms). These observations indicate that active movement of the arm is necessary to trigger short-latency SP of self-moved targets. 4. Despite the lack of proprioceptive information about arm motion, the two deafferented subjects produced early SP (-8 ms on average) when they actively moved their arms. In this respect they did not differ from control subjects. Active control of the arm is thus sufficient to trigger short-latency SP. However, in contrast with control subjects, in deafferented subjects SP gain declined with increasing target motion frequency more rapidly in self-moved target tracking than in eye-alone tracking. 5. The deafferented subjects also tracked a self-moved target while the relationship between arm and target motions was altered either by introducing a delay between arm motion and target motion

  12. Relationship of diminished interjoint coordination after stroke to hand path consistency.

    PubMed

    Gera, Geetanjali; Freitas, Sandra Maria Sbeghen Ferreira; Scholz, John Peter

    2016-03-01

    Differences between 12 left-brain (LCVA, 65.4 ± 11.7 years old) and 10 right-brain (RCVA, 61 ± 12.1 years old) chronic stroke survivors and 10 age-matched control adults in coordinating specific joint motions of the arm to stabilize hand path when reaching to a central target were investigated in this study. The importance of coordinating joints to stabilize hand path was tested by comparing results from uncontrolled manifold (UCM) analysis performed on experimental data versus simulated data where the covariation (coordination) between particular joint motions was removed from the original data set. UCM analysis allowed estimation of the joint configuration variance magnitude that led to hand path variability (V ORT), where the extent of increase in V ORT after removing a joint's covariation indicated how well coordinated its motion actually was with those of the other joints. The more strongly coordinated a joint was with other joints, the greater effect removal of its covariance should have on indices of hand path stability. For the paretic arm of stroke survivors, simulated removal of a joint's covariation, mainly that of shoulder with elbow and wrist, led to less change in the magnitude of V ORT compared to the same arm of control subjects. These findings confirm a reduced ability of the motion of proximal joint from paretic arm to combine flexibly with motions of the distal joints to stabilize hand path.

  13. Eye-hand coupling is not the cause of manual return movements when searching.

    PubMed

    Liesker, Hanneke; Brenner, Eli; Smeets, Jeroen B J

    2010-03-01

    When searching for a target with eye movements, saccades are planned and initiated while the visual information is still being processed, so that subjects often make saccades away from the target and then have to make an additional return saccade. Presumably, the cost of the additional saccades is outweighed by the advantage of short fixations. We previously showed that when the cost of passing the target was increased, by having subjects manually move a window through which they could see the visual scene, subjects still passed the target and made return movements (with their hand). When moving a window in this manner, the eyes and hand follow the same path. To find out whether the hand still passes the target and then returns when eye and hand movements are uncoupled, we here compared moving a window across a scene with moving a scene behind a stationary window. We ensured that the required movement of the hand was identical in both conditions. Subjects found the target faster when moving the window across the scene than when moving the scene behind the window, but at the expense of making larger return movements. The relationship between the return movements and movement speed when comparing the two conditions was the same as the relationship between these two when comparing different window sizes. We conclude that the hand passing the target and then returning is not directly related to the eyes doing so, but rather that moving on before the information has been fully processed is a general principle of visuomotor control.

  14. Inhibitory Control Processes and the Strategies That Support Them during Hand and Eye Movements

    PubMed Central

    Schmitt, Lauren M.; Ankeny, Lisa D.; Sweeney, John A.; Mosconi, Matthew W.

    2016-01-01

    Background and Aims: Adaptive behavior depends on the ability to voluntarily suppress context-inappropriate behaviors, a process referred to as response inhibition. Stop Signal tests (SSTs) are the most frequently studied paradigm used to assess response inhibition. Previous studies of SSTs have indicated that inhibitory control behavior can be explained using a common model in which GO and STOP processes are initiated independent from one and another, and the process that is completed first determines whether the behavior is elicited (GO process) or terminated (STOP process). Consistent with this model, studies have indicated that individuals strategically delay their behaviors during SSTs in order to increase their stopping abilities. Despite being controlled by distinct neural systems, prior studies have largely documented similar inhibitory control performance across eye and hand movements. Though, no existing studies have compared the extent to which individuals strategically delay behavior across different effectors is not yet clear. Here, we compared the extent to which inhibitory control processes and the cognitive strategies that support them during oculomotor and manual motor behaviors. Methods: We examined 29 healthy individuals who performed parallel oculomotor and manual motor SSTs. Participants also completed a separate block of GO trials administered prior to the Stop Signal tests to assess baseline reaction times for each effector and reaction time increases during interleaved GO trials of the SST. Results: Our results showed that stopping errors increased for both effectors as the interval between GO and STOP cues was increased (i.e., stop signal delay), but performance deteriorated more rapidly for eye compared to hand movements with increases in stop signal delay. During GO trials, participants delayed the initiation of their responses for each effector, and greater slowing of reaction times on GO trials was associated with increased accuracy on

  15. Hand-Eye Dominance and Depth Perception Effects in Performance on a Basic Laparoscopic Skills Set

    PubMed Central

    Suleman, Rabiya; Yang, Tong; Paige, John; Chauvin, Sheila; Alleyn, Jaime; Brewer, Martha; Johnson, Stephen I.

    2010-01-01

    Objectives: Our study determined whether depth perception defects and hand-eye dominance affect an individual's ability to perform laparoscopic skills. Methods: The study cohort comprised 104 third-year medical students from LSU School of Medicine who completed a questionnaire including information on handedness and were tested for eye dominance and depth perception by using standardized methods. Training sessions involved an initial recorded performance, a 20-minute practice session, followed by a final recorded performance. Recorded sessions were randomized and rated by using a visual analog scale (maximal possible score = 16) based on overall performance (OPS) and depth perception (DPS). A general linear model was used to correlate depth perception defects and hand-eye dominance with assessment scores for OPS and DPS. Results: Students with depth perception defects scored significantly lower on their initial performance than did those with normal depth perception (OPS, 4.80 vs. 7.16, P=0.0008; DPS, 5.25 vs. 6.93, P=0.0195). After training, the depth perception defect group continued to have lower scores compared with the normal depth perception group. However, the 2 groups showed similar increases in pre- to posttraining performance scores (OPS, 3.84 vs. 3.18, P=0.0732). Hand-eye dominance did not significantly affect scores. Conclusions: Depth perception defects appear to compromise an individual's ability to perform basic laparoscopic skills. Individuals with defects can improve their skills by a proportion comparable to that of people with uncompromised depth perception. Differences in hand-eye dominance do not correlate with performance differences in basic laparoscopic skills. Although further research is necessary, the findings indicate that training can be tailored for individuals with depth perception defects to improve laparoscopic performance. PMID:20529525

  16. Hand-eye dominance and depth perception effects in performance on a basic laparoscopic skills set.

    PubMed

    Suleman, Rabiya; Yang, Tong; Paige, John; Chauvin, Sheila; Alleyn, Jaime; Brewer, Martha; Johnson, Stephen I; Hoxsey, Rodney J

    2010-01-01

    Our study determined whether depth perception defects and hand-eye dominance affect an individual's ability to perform laparoscopic skills. The study cohort comprised 104 third-year medical students from LSU School of Medicine who completed a questionnaire including information on handedness and were tested for eye dominance and depth perception by using standardized methods. Training sessions involved an initial recorded performance, a 20-minute practice session, followed by a final recorded performance. Recorded sessions were randomized and rated by using a visual analog scale (maximal possible score = 16) based on overall performance (OPS) and depth perception (DPS). A general linear model was used to correlate depth perception defects and hand-eye dominance with assessment scores for OPS and DPS. Students with depth perception defects scored significantly lower on their initial performance than did those with normal depth perception (OPS, 4.80 vs. 7.16, P=0.0008; DPS, 5.25 vs. 6.93, P=0.0195). After training, the depth perception defect group continued to have lower scores compared with the normal depth perception group. However, the 2 groups showed similar increases in pre- to posttraining performance scores (OPS, 3.84 vs. 3.18, P=0.0732). Hand-eye dominance did not significantly affect scores. Depth perception defects appear to compromise an individual's ability to perform basic laparoscopic skills. Individuals with defects can improve their skills by a proportion comparable to that of people with uncompromised depth perception. Differences in hand-eye dominance do not correlate with performance differences in basic laparoscopic skills. Although further research is necessary, the findings indicate that training can be tailored for individuals with depth perception defects to improve laparoscopic performance.

  17. Hand and Eye Dominance in Sport: Are Cricket Batters Taught to Bat Back-to-Front?

    PubMed

    Mann, David L; Runswick, Oliver R; Allen, Peter M

    2016-09-01

    When first learning to bimanually use a tool to hit a target (e.g., when chopping wood or hitting a golf ball), most people assume a stance that is dictated by their dominant hand. By convention, this means that a 'right-handed' or 'left-handed' stance that places the dominant hand closer to the striking end of the tool is adopted in many sports. The aim of this study was to investigate whether the conventional stance used for bimanual hitting provides the best chance of developing expertise in that task. Our study included 43 professional (international/first-class) and 93 inexperienced (<5 years' experience) cricket batsmen. We determined their batting stance (plus hand and eye dominance) to compare the proportion of batters who adopted a reversed stance when batting (that is, the opposite stance to that expected based on their handedness). We found that cricket batsmen who adopted a reversed stance had a stunning advantage, with professional batsmen 7.1 times more likely to adopt a reversed stance than inexperienced batsmen, independent of whether they batted right or left handed or the position of their dominant eye. Findings imply that batsmen who adopt a conventional stance may inadvertently be batting 'back-to-front' and have a significant disadvantage in the game. Moreover, the results may generalize more widely, bringing into question the way in which other bimanual sporting actions are taught and performed.

  18. Target modality determines eye-head coordination in nonhuman primates: implications for gaze control

    PubMed Central

    Rajala, Abigail Z.

    2011-01-01

    We have studied eye-head coordination in nonhuman primates with acoustic targets after finding that they are unable to make accurate saccadic eye movements to targets of this type with the head restrained. Three male macaque monkeys with experience in localizing sounds for rewards by pointing their gaze to the perceived location of sources served as subjects. Visual targets were used as controls. The experimental sessions were configured to minimize the chances that the subject would be able to predict the modality of the target as well as its location and time of presentation. The data show that eye and head movements are coordinated differently to generate gaze shifts to acoustic targets. Chiefly, the head invariably started to move before the eye and contributed more to the gaze shift. These differences were more striking for gaze shifts of <20–25° in amplitude, to which the head contributes very little or not at all when the target is visual. Thus acoustic and visual targets trigger gaze shifts with different eye-head coordination. This, coupled to the fact that anatomic evidence involves the superior colliculus as the link between auditory spatial processing and the motor system, suggests that separate signals are likely generated within this midbrain structure. PMID:21795625

  19. Meis1 coordinates a network of genes implicated in eye development and microphthalmia.

    PubMed

    Marcos, Séverine; González-Lázaro, Monica; Beccari, Leonardo; Carramolino, Laura; Martin-Bermejo, Maria Jesus; Amarie, Oana; Mateos-San Martín, Daniel; Torroja, Carlos; Bogdanović, Ozren; Doohan, Roisin; Puk, Oliver; Hrabě de Angelis, Martin; Graw, Jochen; Gomez-Skarmeta, Jose Luis; Casares, Fernando; Torres, Miguel; Bovolenta, Paola

    2015-09-01

    Microphthalmos is a rare congenital anomaly characterized by reduced eye size and visual deficits of variable degree. Sporadic and hereditary microphthalmos have been associated with heterozygous mutations in genes fundamental for eye development. Yet, many cases are idiopathic or await the identification of molecular causes. Here we show that haploinsufficiency of Meis1, which encodes a transcription factor with evolutionarily conserved expression in the embryonic trunk, brain and sensory organs, including the eye, causes microphthalmic traits and visual impairment in adult mice. By combining analysis of Meis1 loss-of-function and conditional Meis1 functional rescue with ChIP-seq and RNA-seq approaches we show that, in contrast to its preferential association with Hox-Pbx BSs in the trunk, Meis1 binds to Hox/Pbx-independent sites during optic cup development. In the eye primordium, Meis1 coordinates, in a dose-dependent manner, retinal proliferation and differentiation by regulating genes responsible for human microphthalmia and components of the Notch signaling pathway. In addition, Meis1 is required for eye patterning by controlling a set of eye territory-specific transcription factors, so that in Meis1(-/-) embryos boundaries among the different eye territories are shifted or blurred. We propose that Meis1 is at the core of a genetic network implicated in eye patterning/microphthalmia, and represents an additional candidate for syndromic cases of these ocular malformations.

  20. Enhanced hybrid electromyogram/Eye Gaze Tracking cursor control system for hands-free computer interaction.

    PubMed

    Chin, Craig A; Barreto, Armando

    2006-01-01

    This paper outlines the development and initial testing of a new hybrid computer cursor control system based on Eye Gaze Tracking (EGT) and electromyogram (EMG) processing for hands-free control of the computer cursor. The ultimate goal of the system is to provide an efficient computer interaction mechanism for individuals with severe motor disabilities (or specialized operators whose hands are committed to other tasks, such as surgeons, pilots, etc.) The paper emphasizes the enhancements that have been made on different areas of the architecture, with respect to a previous prototype developed by our group, and demonstrates the performance improvement verified for some of the enhancements.

  1. Radiation exposure of eyes, thyroid gland and hands in orthopaedic staff: a systematic review.

    PubMed

    Kesavachandran, Chandrasekharan Nair; Haamann, Frank; Nienhaus, Albert

    2012-10-30

    Various procedures, especially minimal invasive techniques using fluoroscopy, pose a risk of radiation exposure to orthopaedic staff. Anatomical sites such as the eyes, thyroid glands and hands are more vulnerable to radiation considering the limited use of personal protective devices in the workplace. The objective of the study is to assess the annual mean cumulative and per procedure radiation dose received at anatomical locations like eyes, thyroid glands and hands in orthopaedic staff using systematic review. The review of literature was conducted using systematic search of the database sources like PUBMED and EMBASE using appropriate keywords. The eligibility criteria and the data extraction of literature were based on study design (cohort or cross-sectional study), study population (orthopaedic surgeons or their assistants), exposure (doses of workplace radiation exposure at hands/fingers, eye/forehead, neck/thyroid), language (German and English). The literature search was conducted using a PRISMA checklist and flow chart. Forty-two articles were found eligible and included for the review. The results show that radiation doses for the anatomical locations of eye, thyroid gland and hands were lower than the dose levels recommended. But there is a considerable variation of radiation dose received at all three anatomical locations mainly due to different situations including procedures (open and minimally invasive), work experience (junior and senior surgeons),distance from the primary and secondary radiation, and use of personal protective equipments (PPEs). The surgeons receive higher radiation dose during minimally invasive procedures compared to open procedures. Junior surgeons are at higher risk of radiation exposure compared to seniors. PPEs play a significant role in reduction of radiation dose. Although the current radiation precautions appear to be adequate based on the low dose radiation, more in-depth studies are required on the variations of

  2. Writing and reading: connections between language by hand and language by eye.

    PubMed

    Berninger, Virginia W; Abbott, Robert D; Abbott, Sylvia P; Graham, Steve; Richards, Todd

    2002-01-01

    Four approaches to the investigation of connections between language by hand and language by eye are described and illustrated with studies from a decade-long research program. In the first approach, multigroup structural equation modeling is applied to reading and writing measures given to typically developing writers to examine unidirectional and bidirectional relationships between specific components of the reading and writing systems. In the second approach, structural equation modeling is applied to a multivariate set of language measures given to children and adults with reading and writing disabilities to examine how the same set of language processes is orchestrated differently to accomplish specific reading or writing goals, and correlations between factors are evaluated to examine the level at which the language-by-hand system and the language-by-eye system communicate most easily. In the third approach, mode of instruction and mode of response are systematically varied in evaluating effectiveness of treating reading disability with and without a writing component. In the fourth approach, functional brain imaging is used to investigate residual spelling problems in students whose problems with word decoding have been remediated. The four approaches support a model in which language by hand and language by eye are separate systems that interact in predictable ways.

  3. Integration of Hand and Finger Location in External Spatial Coordinates for Tactile Localization

    ERIC Educational Resources Information Center

    Heed, Tobias; Backhaus, Jenny; Roder, Brigitte

    2012-01-01

    Tactile stimulus location is automatically transformed from somatotopic into external spatial coordinates, rendering information about the location of touch in three-dimensional space. This process is referred to as tactile remapping. Whereas remapping seems to occur automatically for the hands and feet, the fingers may constitute an exception in…

  4. Integration of Hand and Finger Location in External Spatial Coordinates for Tactile Localization

    ERIC Educational Resources Information Center

    Heed, Tobias; Backhaus, Jenny; Roder, Brigitte

    2012-01-01

    Tactile stimulus location is automatically transformed from somatotopic into external spatial coordinates, rendering information about the location of touch in three-dimensional space. This process is referred to as tactile remapping. Whereas remapping seems to occur automatically for the hands and feet, the fingers may constitute an exception in…

  5. Give Me a Hand! Digitizing Images into a Graphing Calculator Using Coordinate Geometry.

    ERIC Educational Resources Information Center

    Bumbaca, Leonard

    This paper describes a classroom, instructor-led activity designed to show how graphic calculators can be used to explore coordinate geometry. The activity involves digitizing an image of a hand and transforming the image through geometrical transformations. Teaching notes and calculator instructions are included as are blackline masters. Also…

  6. Diminished joint coordination with aging leads to more variable hand paths.

    PubMed

    Dutta, Geetanjali Gera; Freitas, Sandra Maria Sbeghen Ferreira; Scholz, John Peter

    2013-08-01

    Differences in joint coordination between arms and due to aging were studied in healthy young and older adults reaching to either a fixed, central target or to the same target when it could unexpectedly change location after reach initiation. Joint coordination was investigated by artificially removing the covariation of each joint's motions with other joints' motions. Uncontrolled manifold analysis was used to partition joint configuration variance into variance reflecting motor abundance (VUCM) and variance causing hand path variability (VORT). The extent to which VORT, related to the consistency of the hand path, increased after removing a joint's covariation indicated the strength of its coordination with other joints. Young adults exhibited stronger indices of joint coordination, evidenced by a larger increase in VORT after removing joint covariation than for older adults. This effect was more striking for the dominant right compared to the left arm for young adults, but not for older adults, especially with target uncertainty. The results indicate that interjoint coordination in young adults leads to less hand path variability compared to older adults. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. DIMINISHED JOINT COORDINATION WITH AGING LEADS TO MORE VARIABLE HAND PATHS

    PubMed Central

    Dutta, Geetanjali Gera; Freitas, Sandra Maria Sbeghen Ferreira; Scholz, John Peter

    2013-01-01

    Differences in joint coordination between arms and due to aging were studied in healthy young and older adults reaching to either a fixed, central target or to the same target when it could unexpectedly change location after reach initiation. Joint coordination was investigated by artificially removing the covariation of each joint’s motions with other joints’ motions. Uncontrolled manifold analysis was used to partition joint configuration variance into variance reflecting motor abundance (VUCM) and variance causing hand path variability (VORT). The extent to which VORT, related to the consistency of the hand path, increased after removing a joint’s covariation indicated the strength of its coordination with other joints. Young adults exhibited stronger indices of joint coordination, evidenced by a larger increase in VORT after removing joint covariation than for older adults. This effect was more striking for the dominant right compared to the left arm for young adults, but not for older adults, especially with target uncertainty. The results indicate that interjoint coordination in young adults leads to less hand path variability compared to older adults. PMID:23906435

  8. Effect of hand paddles and parachute on the index of coordination of competitive crawl-strokers.

    PubMed

    Telles, Thiago; Barbosa, Augusto C; Campos, Mario H; Junior, Orival Andries

    2011-02-01

    We investigated the effects of hand paddles and parachute on the relative duration of stroke phases and index of coordination of competitive crawl-strokers. Eleven male-swimmers (age: 21.9 ± 4.5 years; 50-m best time: 24.23 ± 0.75 s) were evaluated in four maximal-intensity conditions: without equipment, with hand paddles, with parachute, and with both hand paddles and parachute. Relative stroke phase duration of each arm, swimming velocity, and stroke rate were analysed from video (60 Hz). The index of coordination was quantified based on the lag time between propulsive phases of each arm, which defined the coordination mode as catch-up, opposition or superposition. The stroke rate decreased in all conditions (P < 0.05) and swimming velocity decreased with parachute and with paddles + parachutes (P < 0.05). The coordination mode changed from catch-up in free swimming (-2.3 ± 5.0%) to opposition with paddles (-0.2 ± 3.8%), parachute (0.1 ± 3.1%), and paddles + parachute (0.0 ± 3.2%). Despite these variations, no significant differences were observed in relative duration of right and left arm-stroke phases, or in index of coordination. We conclude that the external resistances analysed do not significantly influence stroke phase organization, but, as a chronic effect, may lead to greater propulsive continuity.

  9. Effect of hand paddles and parachute on backstroke coordination and stroke parameters.

    PubMed

    Telles, Thiago; Barroso, Renato; Figueiredo, Pedro; Salgueiro, Diego Fortes de Souza; Vilas-Boas, João Paulo; Junior, Orival Andries

    2017-05-01

    Hand paddles and parachutes have been used in order to overload swimmers, and consequently increase the propulsive force generation in swimming. However, their use may affect not only kinematical parameters (average speed, stroke length and stroke rate), but also time gaps between propulsive phases, assessed through the index of coordination (IdC). The objective of this study was to assess the effects of hand paddles and parachute use, isolated or combined, on kinematical parameters and coordination. Eleven swimmers (backstroke 50-m time: 29.16 ± 1.43 s) performed four 15-m trials in a randomised order at maximal intensity: (1) without implements (FREE), (2) with hand paddles (HPD), (3) with parachute (PCH) and (4) with hand paddles plus parachute (HPD+PCH). All trials were video-recorded (60 Hz) in order to assess average speed, stroke rate, stroke length, five stroke phases and index of coordination. When average swimming speed was compared to FREE, it was lower in PCH and HPD+PCH, and higher in HPD. Stroke rate decreased in all overloaded trials compared to FREE. The use of hand paddles and parachute increased and decreased stroke length, respectively. In addition, propulsive phase duration was increased when hand paddles were used, and time gaps shifted towards zero (no time gap), especially when hand paddles were combined with parachute. It is conceivable that the combined use of hand paddles and parachute, once allowing overloading both propulsive and resistive forces, provides a specific stimulus to improve muscle strength and propulsive continuity.

  10. Coordinated upper limb training assisted with an electromyography (EMG)-driven hand robot after stroke.

    PubMed

    Hu, X L; Tong, K Y; Wei, X J; Rong, W; Susanto, E A; Ho, S K

    2013-01-01

    An electromyography (EMG)-driven hand robot had been developed for post-stroke rehabilitation training. The effectiveness of the hand robot assisted whole upper limb training on muscular coordination was investigated on persons with chronic stroke (n=10) in this work. All subjects attended a 20-session training (3-5 times/week) by using the hand robot to practice object grasp/release and arm transportation tasks. Improvements were found in the muscle co-ordination between the antagonist muscle pair (flexor digitorum and extensor digitorum) as measured by muscle co-contractions in EMG signals; and also in the reduction of excessive muscle activities in the biceps brachii. Reduced spasticity in the fingers was also observed as measured by the Modified Ashworth Score.

  11. Difference in Activity in the Supplementary Motor Area Depending on Limb Combination of Hand-Foot Coordinated Movements.

    PubMed

    Nakagawa, Kento; Kawashima, Saeko; Mizuguchi, Nobuaki; Kanosue, Kazuyuki

    2016-01-01

    Periodic interlimb coordination shows lower performance when the ipsilateral hand and foot (e.g., right hand and right foot) are simultaneously moved than when the contralateral hand and foot (e.g., right hand and left foot) are simultaneously moved. The present study aimed to investigate how brain activity that is related to the dependence of hand-foot coordination on limb combination, using functional magnetic imaging. Twenty-one right-handed subjects performed periodic coordinated movements of the ipsilateral or contralateral hand and foot in the same or opposite direction in the sagittal plane. Kinematic data showed that performance was lower for the ipsilateral hand-foot coordination than for the contralateral one. A comparison of brain activity between the same and opposite directions showed that there was a greater activation of supplementary motor area for ipsilateral hand-foot coordination as compared to that seen during contralateral hand-foot coordination. We speculate that this might reflect a difference in the degree of inhibition of the neural circuit that disrupts opposite directional movements between ipsilateral and contralateral hand-foot coordinated movements.

  12. Dissociable processing of temporal structure in repetitive eye-hand movements in Parkinson's disease.

    PubMed

    Ventre-Dominey, Jocelyne; Dominey, Peter Ford; Broussolle, Emmanuel

    2002-01-01

    Movement takes place in multiple dimensions, including the temporal dimension, which itself may be made up of dissociable aspects. From this perspective, the present research tests three hypotheses: first, that the generation of regular, repetitive movement frequency is neurophysiologically dissociable from the generation of appropriate phase relations, or latencies, of such movements with respect to external stimuli; second, that the frontostriatal system is critically involved in the control of latency and not frequency and third that while the control of latency is closely linked to the effector motor system (e.g. eye, hand, etc.) the control of movement frequency is a more centralized function. These three hypotheses were investigated in nine Parkinson's disease (PD) patients with asymmetric akinetic-rigid syndrome and in nine age-matched control subjects in the context of repetitive eye-hand movements generated in response to regularly displaced visual stimuli and then the continuation of these movements in the immediate absence of the stimuli. PD patients demonstrated increased latencies for pointing movements, particularly with the affected hand, while their ability to follow and then reproduce the movement frequency remained largely intact. Interestingly, saccade latency was improved for controls and PD patients when pointing with the Less-affected hand and impaired with the More-affected hand. In contrast, saccade frequency was unaffected in these pointing conditions. These results support the hypothesis that movement frequency and latency controls are dissociable, with the frontostriatal system playing an important role in latency but not frequency control. The fact that pointing and saccade latency displayed a hand-effect, while movement frequency did not, also tends to support the hypothesis that latency control is linked to specific motor systems, including their interaction, whereas frequency control is more centralized.

  13. Grammatical number processing and anticipatory eye movements are not tightly coordinated in English spoken language comprehension.

    PubMed

    Riordan, Brian; Dye, Melody; Jones, Michael N

    2015-01-01

    Recent studies of eye movements in world-situated language comprehension have demonstrated that rapid processing of morphosyntactic information - e.g., grammatical gender and number marking - can produce anticipatory eye movements to referents in the visual scene. We investigated how type of morphosyntactic information and the goals of language users in comprehension affected eye movements, focusing on the processing of grammatical number morphology in English-speaking adults. Participants' eye movements were recorded as they listened to simple English declarative (There are the lions.) and interrogative (Where are the lions?) sentences. In Experiment 1, no differences were observed in speed to fixate target referents when grammatical number information was informative relative to when it was not. The same result was obtained in a speeded task (Experiment 2) and in a task using mixed sentence types (Experiment 3). We conclude that grammatical number processing in English and eye movements to potential referents are not tightly coordinated. These results suggest limits on the role of predictive eye movements in concurrent linguistic and scene processing. We discuss how these results can inform and constrain predictive approaches to language processing.

  14. Grammatical number processing and anticipatory eye movements are not tightly coordinated in English spoken language comprehension

    PubMed Central

    Riordan, Brian; Dye, Melody; Jones, Michael N.

    2015-01-01

    Recent studies of eye movements in world-situated language comprehension have demonstrated that rapid processing of morphosyntactic information – e.g., grammatical gender and number marking – can produce anticipatory eye movements to referents in the visual scene. We investigated how type of morphosyntactic information and the goals of language users in comprehension affected eye movements, focusing on the processing of grammatical number morphology in English-speaking adults. Participants’ eye movements were recorded as they listened to simple English declarative (There are the lions.) and interrogative (Where are the lions?) sentences. In Experiment 1, no differences were observed in speed to fixate target referents when grammatical number information was informative relative to when it was not. The same result was obtained in a speeded task (Experiment 2) and in a task using mixed sentence types (Experiment 3). We conclude that grammatical number processing in English and eye movements to potential referents are not tightly coordinated. These results suggest limits on the role of predictive eye movements in concurrent linguistic and scene processing. We discuss how these results can inform and constrain predictive approaches to language processing. PMID:25999900

  15. The effects of eye coordination during deep cervical flexor training on the thickness of the cervical flexors

    PubMed Central

    Moon, Hyun-Ju; Goo, Bong-Oh; Kwon, Hae-Yeon; Jang, Jun-Hyeok

    2015-01-01

    [Purpose] The purpose of this study was to identify changes in the thicknesses of the cervical flexors according to eye coordination during deep cervical flexor training. [Subjects and Methods] Twenty normal adults were randomly selected, and during their deep cervical flexor training and eye tracking, the thicknesses of the longus colli and the sternocleidomastoid were measured using ultrasonic waves. [Results] The thickness of the longus colli statistically significantly increased when deep cervical flexor training and eye coordination were performed simultaneously. However, the thickness of the sternocleidomastoid did not show statistically significant differences according to eye coordination. [Conclusion] Eye coordination during deep cervical flexor training is likely to increase the thickness of the longus colli selectively. PMID:26834355

  16. Hand skill and hand-eye preference in relation to verbal ability in healthy adult male and female right-handers.

    PubMed

    Gorynia, Inge; Müller, Jens

    2006-09-01

    Verbal as well as non-verbal performances were investigated in relation to both hand skill assessed by finger-tapping performances and hand-eye preference in 83 healthy adult right-handers, most of them students. The primary objective of this study was to show better finger-tapping performances in right-handed participants with best verbal IQ values. We found that it was not the non-verbal but the verbal abilities that were related to finger-tapping performances. This was proven, especially as to the left-hand taps. Faster left-hand taps in participants with higher verbal IQ values may be due to a closer cooperation of right-hemispheric regions in information processing and an intimate relationship between language and finger-motor functions. Secondary objectives assessed by explorative data analyses included gender differences and hand-eye preference. While in the females left-hand taps correlated somewhat more with verbal IQ values, in the males this effect was seen in selected variables of the right-hand taps. Moreover, laterality assessed in finger-tapping performances may not be in accordance with laterality found in the handedness questionnaire. In addition to this, congruent hand-eye dominance was found to be slightly more prevalent in participants with best verbal IQ values. However, these findings will have to be confirmed in further experiments.

  17. Sensorimotor and Motivational Determinants of Hand-Mouth Coordination in One-Three-Day-Old Human Infants.

    ERIC Educational Resources Information Center

    Blass, Elliott M.; And Others

    1989-01-01

    Studied hand-mouth coordination in 40 infants of 1-3 days. Sucrose solution was delivered intraorally every 2 minutes. Results provide evidence for sucrose as a calming agent and for a coordinative behavorial system that integrates hand-mouth activity in supine human infants. (RJC)

  18. Eye and hand motor interactions with the Symbol Digit Modalities Test in early multiple sclerosis.

    PubMed

    Nygaard, Gro O; de Rodez Benavent, Sigrid A; Harbo, Hanne F; Laeng, Bruno; Sowa, Piotr; Damangir, Soheil; Bernhard Nilsen, Kristian; Etholm, Lars; Tønnesen, Siren; Kerty, Emilia; Drolsum, Liv; Inge Landrø, Nils; Celius, Elisabeth G

    2015-11-01

    Eye and hand motor dysfunction may be present early in the disease course of relapsing-remitting multiple sclerosis (RRMS), and can affect the results on visual and written cognitive tests. We aimed to test for differences in saccadic initiation time (SI time) between RRMS patients and healthy controls, and whether SI time and hand motor speed interacted with the written version of the Symbol Digit Modalities Test (wSDMT). Patients with RRMS (N = 44, age 35.1 ± 7.3 years), time since diagnosis < 3 years and matched controls (N = 41, age 33.2 ± 6.8 years) were examined with ophthalmological, neurological and neuropsychological tests, as well as structural MRI (white matter lesion load (WMLL) and brainstem lesions), visual evoked potentials (VEP) and eye-tracker examinations of saccades. SI time was longer in RRMS than controls (p < 0.05). SI time was not related to the Paced Auditory Serial Addition Test (PASAT), WMLL or to the presence of brainstem lesions. 9 hole peg test (9HP) correlated significantly with WMLL (r = 0.58, p < 0.01). Both SI time and 9HP correlated negatively with the results of wSDMT (r = -0.32, p < 0.05, r = -0.47, p < 0.01), but none correlated with the results of PASAT. RRMS patients have an increased SI time compared to controls. Cognitive tests results, exemplified by the wSDMT, may be confounded by eye and hand motor function. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  19. Significance of crossed eye-hand dominance for the adult neuropsychological evaluation.

    PubMed

    Swiercinsky, D P

    1977-08-01

    The variable of opposit eye and hand dominance is reviewed as a possible sign of learning problems and as an indication of congenital or early developmental brain impairment. It is considered as an independent variable in examining differences along several dimensions of psychological functioning as a possible discriminator of performance levels. It is also considered as a variable in discriminant function analysis to predict brain lesion process. Although few results were statistically significant, the numerous analyses were remarkably convergent in suggesting that crossed dominance is related to poorer verbal learning skills and is a useful variable in differentiating various process diagnostic groups.

  20. Age- and Stereovision-Dependent Eye–Hand Coordination Deficits in Children With Amblyopia and Abnormal Binocularity

    PubMed Central

    Grant, Simon; Suttle, Catherine; Melmoth, Dean R.; Conway, Miriam L.; Sloper, John J.

    2014-01-01

    Purpose. To examine factors contributing to eye–hand coordination deficits in children with amblyopia and impaired stereovision. Methods. Participants were 55 anisometropic or strabismic children aged 5.0 to 9.25 years with different degrees of amblyopia and abnormal binocularity, along with 28 age-matched visually-normal controls. Pilot data were obtained from four additional patients studied longitudinally at different treatment stages. Movements of the preferred hand were recorded using a 3D motion-capture system while subjects reached-to-precision grasp objects (two sizes, three locations) under binocular, dominant eye, and amblyopic/nonsighting eye conditions. Kinematic and “error” performance measures were quantified and compared by viewing condition and subject group using ANOVA, stepwise regression, and correlation analyses. Results. Movements of the younger amblyopes (age 5–6 years; n = 30) were much slower, particularly in the final approach to the objects, and contained more spatial errors in reaching (∼×1.25–1.75) and grasping (∼×1.75–2.25) under all three views (P < 0.05) than their age-matched controls (n = 13). Amblyopia severity was the main contributor to their slower movements with absent stereovision a secondary factor and the unique determinant of their increased error-rates. Older amblyopes (age 7–9 years; n = 25) spent longer contacting the objects before lifting them (P = 0.015) compared with their matched controls (n = 15), with absence of stereovision still solely related to increases in reach and grasp errors, although these occurred less frequently than in younger patients. Pilot prospective data supported these findings by showing positive treatment-related associations between improved stereovision and reach-to-grasp performance. Conclusions. Strategies that children with amblyopia and abnormal binocularity use for reach-to-precision grasping change with age, from emphasis on visual feedback during the

  1. Characterizing coordination of grasp and twist in hand function of healthy and post-stroke subjects.

    PubMed

    Kazemi, Hamed; Kearney, Robert; Milner, Theodore

    2013-06-01

    The goal of this study was to characterize the coordination of grasp and twist in hand function of normal and post-stroke subjects using a two degree of freedom hand robot. Results of the analysis of data from eight control subjects indicated that normal grip coordination involves the linear modulation of grip force with load torque. Thus, there was a high correlation between grip force and load torque. Also, the force generated by the thumb was highly correlated with the force generated by the index, middle and ring fingers. Finally, the safety margin used to stabilize grasp and avoid slip was consistent across normal subjects. In contrast, results from chronic post-stroke subjects indicated that they generally: (1) exerted excessive grip force to stabilize grasp using their ipsilesional hand; (2) lost the close amplitude coupling between grip force and load torque; and (3) lost the close modulation of the thumb force with finger force. These results suggest that our methods may provide objective, quantitative means of characterizing coordination problems following stroke.

  2. A neurophysiological basis for the coordination between hand and foot movement.

    PubMed

    McIntyre-Robinson, Andrew J K; Byblow, Winston D

    2013-09-01

    Hand and foot movements are made more reliably when both limbs move in the same direction at the same time (isodirectional) compared with when they are made in opposite directions (anisodirectional). We hypothesized that M1 intracortical facilitation may subserve hand-foot coordination and reveal correlates that explain the preference for hand-foot movements to be performed in an isodirectional pattern. To test our hypothesis we investigated behavioral kinematics of hand-foot coordination (experiment 1) and neurophysiological measures of corticomotor excitability and intracortical facilitation (experiment 2) in 17 healthy young adults. As expected, coordination became unstable in the anisodirectional pattern but not the isodirectional pattern, as confirmed in measures of wrist and ankle relative phase error and stability (both P < 0.001). Short-latency paired-pulse TMS was used to elicit motor evoked potentials (MEPs) and produce short-latency intracortical facilitation (sICF) in right extensor carpi radialis (ECR) and flexor carpi radialis (FCR) in the presence and absence of right ankle plantarflexion/dorsiflexion (P < 0.015). An isodirectional preference was confirmed by facilitation of FCR MEPs and TMS-induced wrist flexion during ankle plantarflexion (both P < 0.025) but no evidence of modulation of any particular "I wave" during foot movement compared with rest. A novel finding was the association between loss of stability of the anisodirectional pattern (experiment 1) and the modulation of corticomotor excitability in support of the isodirectional pattern (experiment 2) (P < 0.05). The preference for isodirectional hand-foot movements appears not to depend on M1 intracortical facilitation.

  3. Do bimanual coordination, tool use, and body posture contribute equally to hand preferences in bonobos?

    PubMed

    Bardo, Ameline; Pouydebat, Emmanuelle; Meunier, Hélène

    2015-05-01

    Approximately 90% of the human population is right-handed. The emergence of this hand preference in humans is thought to be linked to the ability to execute complex tasks and habitual bipedalism. In order to test these hypotheses, the present study explored, for the first time, hand preference in relation to both body posture (seated and bipedal) and task complexity (bimanual coordination and two tool use tasks of different complexity) in bonobos (Pan paniscus). Few studies have explored the effects of both posture and task complexity on handedness, and investigations with bonobos are scarce, particularly studies on tool use. Our study aims to overcome such a gap by addressing two main questions: 1) Does a bipedal posture increase the strength of hand preference and/or create a directional bias to the use of the right hand? 2) Independent of body posture, does task complexity increase the strength of the hand preference and/or create a directional bias to the use of the right hand? Our results show that independent of body posture, the more complex the task, the more lateralization occurred. Moreover, subjects tended to be right-handed for tasks involving tool use. However, posture had no significant effect on hand preference in the tasks tested here. Therefore, for a given task, bonobos were not more lateralized in a bipedal posture than in a seated one. Task complexity might thus have contributed more than bipedal posture to the emergence of human lateralization and the preponderance of right-handedness, although a larger sample size and more data are needed to be conclusive. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. The eye in hand: predicting others' behavior by integrating multiple sources of information.

    PubMed

    Ambrosini, Ettore; Pezzulo, Giovanni; Costantini, Marcello

    2015-04-01

    The ability to predict the outcome of other beings' actions confers significant adaptive advantages. Experiments have assessed that human action observation can use multiple information sources, but it is currently unknown how they are integrated and how conflicts between them are resolved. To address this issue, we designed an action observation paradigm requiring the integration of multiple, potentially conflicting sources of evidence about the action target: the actor's gaze direction, hand preshape, and arm trajectory, and their availability and relative uncertainty in time. In two experiments, we analyzed participants' action prediction ability by using eye tracking and behavioral measures. The results show that the information provided by the actor's gaze affected participants' explicit predictions. However, results also show that gaze information was disregarded as soon as information on the actor's hand preshape was available, and this latter information source had widespread effects on participants' prediction ability. Furthermore, as the action unfolded in time, participants relied increasingly more on the arm movement source, showing sensitivity to its increasing informativeness. Therefore, the results suggest that the brain forms a robust estimate of the actor's motor intention by integrating multiple sources of information. However, when informative motor cues such as a preshaped hand with a given grip are available and might help in selecting action targets, people tend to capitalize on such motor cues, thus turning out to be more accurate and fast in inferring the object to be manipulated by the other's hand. Copyright © 2015 the American Physiological Society.

  5. The eye in hand: predicting others' behavior by integrating multiple sources of information

    PubMed Central

    Pezzulo, Giovanni; Costantini, Marcello

    2015-01-01

    The ability to predict the outcome of other beings' actions confers significant adaptive advantages. Experiments have assessed that human action observation can use multiple information sources, but it is currently unknown how they are integrated and how conflicts between them are resolved. To address this issue, we designed an action observation paradigm requiring the integration of multiple, potentially conflicting sources of evidence about the action target: the actor's gaze direction, hand preshape, and arm trajectory, and their availability and relative uncertainty in time. In two experiments, we analyzed participants' action prediction ability by using eye tracking and behavioral measures. The results show that the information provided by the actor's gaze affected participants' explicit predictions. However, results also show that gaze information was disregarded as soon as information on the actor's hand preshape was available, and this latter information source had widespread effects on participants' prediction ability. Furthermore, as the action unfolded in time, participants relied increasingly more on the arm movement source, showing sensitivity to its increasing informativeness. Therefore, the results suggest that the brain forms a robust estimate of the actor's motor intention by integrating multiple sources of information. However, when informative motor cues such as a preshaped hand with a given grip are available and might help in selecting action targets, people tend to capitalize on such motor cues, thus turning out to be more accurate and fast in inferring the object to be manipulated by the other's hand. PMID:25568158

  6. Generalization of motor resonance during the observation of hand, mouth, and eye movements.

    PubMed

    Finisguerra, Alessandra; Maffongelli, Laura; Bassolino, Michela; Jacono, Marco; Pozzo, Thierry; D'Ausilio, Alessandro

    2015-10-01

    Transcranial magnetic stimulation (TMS) of the motor cortex shows that hand action observation (AO) modulates corticospinal excitability (CSE). CSE modulation alternatively maps low-level kinematic characteristics or higher-level features, like object-directed action goals. However, action execution is achieved through the control of muscle synergies, consisting of coordinated patterns of muscular activity during natural movements, rather than single muscles or object-directed goals. This synergistic organization of action execution also underlies the ability to produce the same functional output (i.e., grasping an object) using different effectors. We hypothesize that motor system activation during AO may rely on similar principles. To investigate this issue, we recorded both hand CSE and TMS-evoked finger movements which provide a much more complete description of coordinated patterns of muscular activity. Subjects passively watched hand, mouth and eyelid opening or closing, which are performing non-object-directed (intransitive) actions. Hand and mouth share the same potential to grasp objects, whereas eyelid does not allow object-directed (transitive) actions. Hand CSE modulation generalized to all effectors, while TMS evoked finger movements only to mouth AO. Such dissociation suggests that the two techniques may have different sensitivities to fine motor modulations induced by AO. Differently from evoked movements, which are sensitive to the possibility to achieve object-directed action, CSE is generically modulated by "opening" vs. "closing" movements, independently of which effector was observed. We propose that motor activities during AO might exploit the same synergistic mechanisms shown for the neural control of movement and organized around a limited set of motor primitives. Copyright © 2015 the American Physiological Society.

  7. A Teaching Eye Model for Ophthalmoscopy.

    ERIC Educational Resources Information Center

    Miller, David

    1981-01-01

    A teaching eye model that allows the medical student to learn the hand-eye coordination and associated thinking patterns that allow for a more sophisticated use of the ophthalmoscope is described. The eye teaching model attempted to simulate the features found in the eye of a real patient. (MLW)

  8. Moving a hand-held object: Reconstruction of referent coordinate and apparent stiffness trajectories

    PubMed Central

    Ambike, Satyajit; Zhou, Tao; Zatsiorsky, Vladimir M.; Latash, Mark L.

    2015-01-01

    This study used the framework of the referent configuration hypothesis and slow changes in the external conditions during vertical oscillation of a hand-held object to infer the characteristics of hypothetical control variables. The study had two main objectives: (1) to show that hypothetical control variables, namely, referent coordinates and apparent stiffness of vertical hand position and grip force can be measured in an experiment; and (2) to establish relation(s) between these control variables that yield the classic grip-force-load-force coupling. Healthy subjects gripped a handle and performed vertical oscillations between visual targets at one of five metronome-prescribed frequencies. A Hapticmaster robot was used to induce slow changes in the vertical force applied to the handle, while the size of the handle was changed slowly leading to changes in the grip aperture. The subjects were instructed not to react to possible changes in the external forces. A linear, second-order model was used to reconstruct the referent coordinate and apparent stiffness values for each phase of the vertical oscillation cycle using across-cycle regressions. The reconstructed time profiles of the referent coordinates and apparent stiffness showed consistent trends across subjects and movement frequencies. To validate the method, these values were used to predict the vertical force and the grip force applied to the handle for movement cycles that were not utilized in the reconstruction process. Analysis of the coupling between the four variables, two referent coordinates and two apparent stiffness values, revealed a single strong constraint reflecting the coupling between the grip force and vertical force. We view these data as providing experimental support for the idea of controlling natural, multi-muscle actions with shifts in a low-dimensional set of referent coordinates. PMID:25896800

  9. The effects of instruction and hand dominance on grip-to-load force coordination in manipulation tasks.

    PubMed

    Jin, Xin; Uygur, Mehmet; Getchell, Nancy; Hall, Susan J; Jaric, Slobodan

    2011-10-31

    The force applied upon a vertically oriented hand-held object could be decomposed into two orthogonal and highly coordinated components: the grip force (GF; the component perpendicular to the hand-object contact area that provides friction) and the load force (LF; the parallel component that can move the object or support the body). The aim of this study was to investigate the underexplored effects of task instruction and hand dominance on GF-LF coordination. Sixteen right-handed subjects performed bimanual manipulation against a horizontally oriented instrumented device under different sets of instructions. The tasks involved exertion of ramp-and-hold or oscillation patterns of LF performed symmetrically with two hands, while the instructions regarding individual actions were either similar (pull with both hands) or dissimilar (pull with one hand and hold with another). The results revealed that the instruction "to pull" leads to higher indices of GF-LF coordination than the instruction "to hold", as evidenced by a lower GF-LF ratio, higher GF-LF coupling, and higher GF modulation. The only effect of hand dominance was a moderate time lag of GF relative to LF changes observed in the non-dominant hand. We conclude that the instructions could play an important role in GF-LF coordination and, therefore, they should be taken into account when exploring or routinely testing hand function. Additionally, the results suggest that the neural control of GF of the non-dominant hand could involve some feedback mechanisms.

  10. Rapid target foraging with reach or gaze: The hand looks further ahead than the eye.

    PubMed

    Diamond, Jonathan S; Wolpert, Daniel M; Flanagan, J Randall

    2017-07-01

    Real-world tasks typically consist of a series of target-directed actions and often require choices about which targets to act on and in what order. Such choice behavior can be assessed from an optimal foraging perspective whereby target selection is shaped by a balance between rewards and costs. Here we evaluated such decision-making in a rapid movement foraging task. On a given trial, participants were presented with 15 targets of varying size and value and were instructed to harvest as much reward as possible by either moving a handle to the targets (hand task) or by briefly fixating them (eye task). The short trial duration enabled participants to harvest about half the targets, ensuring that total reward was due to choice behavior. We developed a probabilistic model to predict target-by-target harvesting choices that considered the rewards and movement-related costs (i.e., target distance and size) associated with the current target as well as future targets. In the hand task, in comparison to the eye task, target choice was more strongly influenced by movement-related costs and took into account a greater number of future targets, consistent with the greater costs associated with arm movement. In both tasks, participants exhibited near-optimal behaviour and in a constrained version of the hand task in which choices could only be based on target positions, participants consistently chose among the shortest movement paths. Our results demonstrate that people can rapidly and effectively integrate values and movement-related costs associated with current and future targets when sequentially harvesting targets.

  11. Rapid target foraging with reach or gaze: The hand looks further ahead than the eye

    PubMed Central

    2017-01-01

    Real-world tasks typically consist of a series of target-directed actions and often require choices about which targets to act on and in what order. Such choice behavior can be assessed from an optimal foraging perspective whereby target selection is shaped by a balance between rewards and costs. Here we evaluated such decision-making in a rapid movement foraging task. On a given trial, participants were presented with 15 targets of varying size and value and were instructed to harvest as much reward as possible by either moving a handle to the targets (hand task) or by briefly fixating them (eye task). The short trial duration enabled participants to harvest about half the targets, ensuring that total reward was due to choice behavior. We developed a probabilistic model to predict target-by-target harvesting choices that considered the rewards and movement-related costs (i.e., target distance and size) associated with the current target as well as future targets. In the hand task, in comparison to the eye task, target choice was more strongly influenced by movement-related costs and took into account a greater number of future targets, consistent with the greater costs associated with arm movement. In both tasks, participants exhibited near-optimal behaviour and in a constrained version of the hand task in which choices could only be based on target positions, participants consistently chose among the shortest movement paths. Our results demonstrate that people can rapidly and effectively integrate values and movement-related costs associated with current and future targets when sequentially harvesting targets. PMID:28683138

  12. Effect of terminal accuracy requirements on temporal gaze-hand coordination during fast discrete and reciprocal pointings

    PubMed Central

    2011-01-01

    Background Rapid discrete goal-directed movements are characterized by a well known coordination pattern between the gaze and the hand displacements. The gaze always starts prior to the hand movement and reaches the target before hand velocity peak. Surprisingly, the effect of the target size on the temporal gaze-hand coordination has not been directly investigated. Moreover, goal-directed movements are often produced in a reciprocal rather than in a discrete manner. The objectives of this work were to assess the effect of the target size on temporal gaze-hand coordination during fast 1) discrete and 2) reciprocal pointings. Methods Subjects performed fast discrete (experiment 1) and reciprocal (experiment 2) pointings with an amplitude of 50 cm and four target diameters (7.6, 3.8, 1.9 and 0.95 cm) leading to indexes of difficulty (ID = log2[2A/D]) of 3.7, 4.7, 5.7 and 6.7 bits. Gaze and hand displacements were synchronously recorded. Temporal gaze-hand coordination parameters were compared between experiments (discrete and reciprocal pointings) and IDs using analyses of variance (ANOVAs). Results Data showed that the magnitude of the gaze-hand lead pattern was much higher for discrete than for reciprocal pointings. Moreover, while it was constant for discrete pointings, it decreased systematically with an increasing ID for reciprocal pointings because of the longer duration of gaze anchoring on target. Conclusion Overall, the temporal gaze-hand coordination analysis revealed that even for high IDs, fast reciprocal pointings could not be considered as a concatenation of discrete units. Moreover, our data clearly illustrate the smooth adaptation of temporal gaze-hand coordination to terminal accuracy requirements during fast reciprocal pointings. It will be interesting for further researches to investigate if the methodology used in the experiment 2 allows assessing the effect of sensori-motor deficits on gaze-hand coordination. PMID:21320315

  13. Eye Tracking of Occluded Self-Moved Targets: Role of Haptic Feedback and Hand-Target Dynamics.

    PubMed

    Danion, Frederic; Mathew, James; Flanagan, J Randall

    2017-01-01

    Previous studies on smooth pursuit eye movements have shown that humans can continue to track the position of their hand, or a target controlled by the hand, after it is occluded, thereby demonstrating that arm motor commands contribute to the prediction of target motion driving pursuit eye movements. Here, we investigated this predictive mechanism by manipulating both the complexity of the hand-target mapping and the provision of haptic feedback. Two hand-target mappings were used, either a rigid (simple) one in which hand and target motion matched perfectly or a nonrigid (complex) one in which the target behaved as a mass attached to the hand by means of a spring. Target animation was obtained by asking participants to oscillate a lightweight robotic device that provided (or not) haptic feedback consistent with the target dynamics. Results showed that as long as 7 s after target occlusion, smooth pursuit continued to be the main contributor to total eye displacement (∼60%). However, the accuracy of eye-tracking varied substantially across experimental conditions. In general, eye-tracking was less accurate under the nonrigid mapping, as reflected by higher positional and velocity errors. Interestingly, haptic feedback helped to reduce the detrimental effects of target occlusion when participants used the nonrigid mapping, but not when they used the rigid one. Overall, we conclude that the ability to maintain smooth pursuit in the absence of visual information can extend to complex hand-target mappings, but the provision of haptic feedback is critical for the maintenance of accurate eye-tracking performance.

  14. Eye Tracking of Occluded Self-Moved Targets: Role of Haptic Feedback and Hand-Target Dynamics

    PubMed Central

    Mathew, James

    2017-01-01

    Abstract Previous studies on smooth pursuit eye movements have shown that humans can continue to track the position of their hand, or a target controlled by the hand, after it is occluded, thereby demonstrating that arm motor commands contribute to the prediction of target motion driving pursuit eye movements. Here, we investigated this predictive mechanism by manipulating both the complexity of the hand-target mapping and the provision of haptic feedback. Two hand-target mappings were used, either a rigid (simple) one in which hand and target motion matched perfectly or a nonrigid (complex) one in which the target behaved as a mass attached to the hand by means of a spring. Target animation was obtained by asking participants to oscillate a lightweight robotic device that provided (or not) haptic feedback consistent with the target dynamics. Results showed that as long as 7 s after target occlusion, smooth pursuit continued to be the main contributor to total eye displacement (∼60%). However, the accuracy of eye-tracking varied substantially across experimental conditions. In general, eye-tracking was less accurate under the nonrigid mapping, as reflected by higher positional and velocity errors. Interestingly, haptic feedback helped to reduce the detrimental effects of target occlusion when participants used the nonrigid mapping, but not when they used the rigid one. Overall, we conclude that the ability to maintain smooth pursuit in the absence of visual information can extend to complex hand-target mappings, but the provision of haptic feedback is critical for the maintenance of accurate eye-tracking performance. PMID:28680964

  15. "Alien hand" and loss of bimanual coordination after dominant anterior cerebral artery territory infarction.

    PubMed Central

    McNabb, A W; Carroll, W M; Mastaglia, F L

    1988-01-01

    Three patients with dominant anterior cerebral artery territory infarction demonstrated a severe disturbance of upper limb motor control with impaired bimanual coordination, the "alien hand" sign, and intermanual conflict, in addition to signs of callosal interruption and a transcortical motor aphasia. Recordings of movement-related potentials in one patient showed an attenuated Bereitschaftspotential and a greater asymmetry of the NS' component of the premotor negativity with left finger than with right finger movement. The impairment of bimanual motor control and associated abnormal motor behaviour of the right hand in these cases are postulated to be due to involvement of the supplementary motor area and related areas of the medial frontal cortex. Images PMID:3346686

  16. The coordinate system of the eye in cataract surgery: Performance comparison of the circle Hough transform and Daugman's algorithm

    NASA Astrophysics Data System (ADS)

    Vlachynska, Alzbeta; Oplatkova, Zuzana Kominkova; Sramka, Martin

    2017-07-01

    The aim of the work is to determine the coordinate system of an eye and insert a polar-axis system into images captured by a slip lamp. The image of the eye with the polar axis helps a surgeon accurately implant toric intraocular lens in the required position/rotation during the cataract surgery. In this paper, two common algorithms for pupil detection are compared: the circle Hough transform and Daugman's algorithm. The procedures were tested and analysed on the anonymous data set of 128 eyes captured at Gemini eye clinic in 2015.

  17. Line-feature-based calibration method of structured light plane parameters for robot hand-eye system

    NASA Astrophysics Data System (ADS)

    Qi, Yuhan; Jing, Fengshui; Tan, Min

    2013-03-01

    For monocular-structured light vision measurement, it is essential to calibrate the structured light plane parameters in addition to the camera intrinsic parameters. A line-feature-based calibration method of structured light plane parameters for a robot hand-eye system is proposed. Structured light stripes are selected as calibrating primitive elements, and the robot moves from one calibrating position to another with constraint in order that two misaligned stripe lines are generated. The images of stripe lines could then be captured by the camera fixed at the robot's end link. During calibration, the equations of two stripe lines in the camera coordinate system are calculated, and then the structured light plane could be determined. As the robot's motion may affect the effectiveness of calibration, so the robot's motion constraints are analyzed. A calibration experiment and two vision measurement experiments are implemented, and the results reveal that the calibration accuracy can meet the precision requirement of robot thick plate welding. Finally, analysis and discussion are provided to illustrate that the method has a high efficiency fit for industrial in-situ calibration.

  18. Long-Latency Feedback Coordinates Upper-Limb and Hand Muscles during Object Manipulation Tasks.

    PubMed

    Crevecoeur, Frédéric; Thonnard, Jean-Louis; Lefèvre, Philippe; Scott, Stephen H

    2016-01-01

    Suppose that someone bumps into your arm at a party while you are holding a glass of wine. Motion of the disturbed arm will engage rapid and goal-directed feedback responses in the upper-limb. Although such responses can rapidly counter the perturbation, it is also clearly desirable not to destabilize your grasp and/or spill the wine. Here we investigated how healthy humans maintain a stable grasp following perturbations by using a paradigm that requires spatial tuning of the motor response dependent on the location of a virtual target. Our results highlight a synchronized expression of target-directed feedback in shoulder and hand muscles occurring at ∼60 ms. Considering that conduction delays are longer for the more distal hand muscles, these results suggest that target-directed responses in hand muscles were initiated before those for the shoulder muscles. These results show that long-latency feedback can coordinate upper limb and hand muscles during object manipulation tasks.

  19. Long-Latency Feedback Coordinates Upper-Limb and Hand Muscles during Object Manipulation Tasks123

    PubMed Central

    Thonnard, Jean-Louis; Scott, Stephen H.

    2016-01-01

    Suppose that someone bumps into your arm at a party while you are holding a glass of wine. Motion of the disturbed arm will engage rapid and goal-directed feedback responses in the upper-limb. Although such responses can rapidly counter the perturbation, it is also clearly desirable not to destabilize your grasp and/or spill the wine. Here we investigated how healthy humans maintain a stable grasp following perturbations by using a paradigm that requires spatial tuning of the motor response dependent on the location of a virtual target. Our results highlight a synchronized expression of target-directed feedback in shoulder and hand muscles occurring at ∼60 ms. Considering that conduction delays are longer for the more distal hand muscles, these results suggest that target-directed responses in hand muscles were initiated before those for the shoulder muscles. These results show that long-latency feedback can coordinate upper limb and hand muscles during object manipulation tasks. PMID:27022624

  20. I-PORT: new "hands-free" near-eye display

    NASA Astrophysics Data System (ADS)

    Carollo, Jerome T.; Hoppe, Michael

    2007-04-01

    The patent pending I-PORT TM is a highly versatile, hands-free, low profile near-eye display system. It was originally designed with the medical market in mind as a data (monocular) or surgical (binocular) head worn display. The concept takes advantage of a technique used with surgical loupes where they are sometimes mounted "into" eyeglasses. The I-PORT TMdisplay module is similarly mounted onto or into the spectacle lens of protective eyewear or sunglasses. The I-PORT TM is capable of various fields of view and resolutions while being low profile providing minimal obscuration. It is an ideal remote viewer for medical, military and commercial equipment. Our system is capable of producing fields of view greater than 50 degrees in full color and can incorporate either organic light emitting diode, (OLED) or active matrix liquid crystal display (AMLCD) image sources of various resolutions.

  1. An improved robust hand-eye calibration for endoscopy navigation system

    NASA Astrophysics Data System (ADS)

    He, Wei; Kang, Kumsok; Li, Yanfang; Shi, Weili; Miao, Yu; He, Fei; Yan, Fei; Yang, Huamin; Zhang, Huimao; Mori, Kensaku; Jiang, Zhengang

    2016-03-01

    Endoscopy is widely used in clinical application, and surgical navigation system is an extremely important way to enhance the safety of endoscopy. The key to improve the accuracy of the navigation system is to solve the positional relationship between camera and tracking marker precisely. The problem can be solved by the hand-eye calibration method based on dual quaternions. However, because of the tracking error and the limited motion of the endoscope, the sample motions may contain some incomplete motion samples. Those motions will cause the algorithm unstable and inaccurate. An advanced selection rule for sample motions is proposed in this paper to improve the stability and accuracy of the methods based on dual quaternion. By setting the motion filter to filter out the incomplete motion samples, finally, high precision and robust result is achieved. The experimental results show that the accuracy and stability of camera registration have been effectively improved by selecting sample motion data automatically.

  2. Preferential coding of eye/hand motor actions in the human ventral occipito-temporal cortex.

    PubMed

    Tosoni, Annalisa; Guidotti, Roberto; Del Gratta, Cosimo; Committeri, Giorgia; Sestieri, Carlo

    2016-12-01

    The human ventral occipito-temporal cortex (OTC) contains areas specialized for particular perceptual/semantic categories, such as faces (fusiform face area, FFA) and places (parahippocampal place area, PPA). This organization has been interpreted as reflecting the visual structure of the world, i.e. perceptual similarity and/or eccentricity biases. However, recent functional magnetic resonance imaging (fMRI) studies have shown not only that regions of the OTC are modulated by non-visual, action-related object properties but also by motor planning and execution, although the functional role and specificity of this motor-related activity are still unclear. Here, through a reanalysis of previously published data, we tested whether the selectivity for perceptual/semantic categories in the OTC corresponds to a preference for particular motor actions. The results demonstrate for the first time that face- and place-selective regions of the OTC exhibit preferential BOLD response to the execution of hand pointing and saccadic eye movements, respectively. Moreover, multivariate analyses provide novel evidence for the consistency across neural representations of stimulus category and movement effector in OTC. According to a 'spatial hypothesis', this pattern of results originates from the match between the region eccentricity bias and the typical action space of the motor effectors. Alternatively, the double dissociation may be caused by the different effect produced by hand vs. eye movements on regions coding for body representation. Overall, the present findings offer novel insights on the coupling between visual and motor cortical representations. Copyright © 2016. Published by Elsevier Ltd.

  3. The hand grasps the center, while the eyes saccade to the top of novel objects

    PubMed Central

    Juravle, Georgiana; Velasco, Carlos; Salgado-Montejo, Alejandro; Spence, Charles

    2015-01-01

    In the present study, we investigated whether indenting the sides of novel objects (e.g., product packaging) would influence where people grasp, and hence focus their gaze, under the assumption that gaze precedes grasping. In Experiment 1, the participants grasped a selection of custom-made objects designed to resemble typical packaging forms with an indentation in the upper, middle, or lower part. In Experiment 2, eye movements were recorded while the participants viewed differently-sized (small, medium, and large) objects with the same three indentation positions tested in Experiment 1, together with a control object lacking any indentation. The results revealed that irrespective of the location of the indentation, the participants tended to grasp the mid-region of the object, with their index finger always positioned slightly above its midpoint. Importantly, the first visual fixation tended to fall in the cap region of the novel object. The participants also fixated for longer in this region. Furthermore, participants saccaded more often, as well saccading more rapidly when directing their gaze to the upper region of the objects that they were required to inspect visually. Taken together, these results therefore suggest that different spatial locations on target objects are of interest to our eyes and hands. PMID:26052291

  4. Handedness, eyedness, and hand--eye crossed dominance in patients with schizophrenia: sex-related lateralisation abnormalities.

    PubMed

    Dane, Senol; Yildirim, Serap; Ozan, Erol; Aydin, Nazan; Oral, Elif; Ustaoglu, Neriman; Kirpinar, Ismet

    2009-01-01

    Schizophrenia is referred to as cerebral lateralisation abnormality. In this study the possible relationships among handedness, eye dominance, and crossed and non congruent hand-eye dominance in patients with schizophrenia are investigated. A total of 88 patients with schizophrenia and 118 controls were included in the study.The patient group included 60 men and 28 women who ranged in age from 17 to 63 years. Diagnoses were made on the basis of information provided from clinical interviews and Structured Clinical Interview for DSM-IV. Handedness was ascertained by using the Edinburgh Handedness Inventory. Eye dominance was measured only by the near-far alignment test. Patients with schizophrenia had a significantly increased frequency of mixed-handedness and decreased frequency of both right- and left-handedness in comparison with controls. Also, the male patients with schizophrenia had significantly increased frequencies of left eye dominance, crossed hand-eye dominance, and non-congruent hand-eye dominance compared to controls, but not the female patients. Cerebral lateralisation abnormalities in schizophrenia may be associated with sex-related hormonal factors.

  5. Quiet eye distinguishes children of high and low motor coordination abilities.

    PubMed

    Wilson, Mark R; Miles, Charlotte A L; Vine, Samuel J; Vickers, Joan N

    2013-06-01

    This is the first study to use the quiet eye (QE) as an objective measure of visuomotor control underpinning proficiency differences in children's motor coordination. Fifty-seven, year 5 primary school children (9-10 yr old) completed the Movement Assessment Battery for Children, Second Edition (MABC-2), while wearing a gaze registration system. Participants were subsequently divided into one of three ability groups: high motor coordination (HMC), median motor coordination (MMC), and low motor coordination (LMC) based on these MABC-2 scores (mean % rank: HMC = 84%, MMC = 51%, LMC = 19%). QE analyses were performed for the fourth task of the MABC-2, which involved throwing a tennis ball against a wall and catching it on the return. The HMC group was more successful in the catching task than both other groups (catching percentage: HMC = 92%, MMC = 62%, LMC = 35%) and demonstrated superior visuomotor control throughout the throwing and catching phases of the task. Compared with the other groups, the HMC group demonstrated longer targeting QE fixations before the release of the ball (HMC = 500 ms, MMC = 410 ms, LMC = 260 ms) and longer tracking QE durations before catching (HMC = 260 ms, MMC = 200 ms, LMC = 150 ms). There were no significant differences in ball flight time between the groups. Mediation analyses revealed that only the duration of the tracking QE predicted group differences in catching ability. Findings suggest that the ability to predict and calibrate movements based on sensory feedback may be impaired in children with movement coordination difficulties and have implications for how they are taught fundamental movement skills.

  6. Theta and beta synchrony coordinate frontal eye fields and anterior cingulate cortex during sensorimotor mapping

    PubMed Central

    Babapoor-Farrokhran, Sahand; Vinck, Martin; Womelsdorf, Thilo; Everling, Stefan

    2017-01-01

    The frontal eye fields (FEFs) and the anterior cingulate cortex (ACC) are commonly coactivated for cognitive saccade tasks, but whether this joined activation indexes coordinated activity underlying successful guidance of sensorimotor mapping is unknown. Here we test whether ACC and FEF circuits coordinate through phase synchronization of local field potential and neural spiking activity in macaque monkeys performing memory-guided and pro- and anti-saccades. We find that FEF and ACC showed prominent synchronization at a 3–9 Hz theta and a 12–30 Hz beta frequency band during the delay and preparation periods with a strong Granger-causal influence from ACC to FEF. The strength of theta- and beta-band coherence between ACC and FEF but not variations in power predict correct task performance. Taken together, the results support a role of ACC in cognitive control of frontoparietal networks and suggest that narrow-band theta and to some extent beta rhythmic activity indexes the coordination of relevant information during periods of enhanced control demands. PMID:28169987

  7. Association between eye and hand dominance and hitting, fielding and pitching skill among players of the Southern Baseball League.

    PubMed

    Classe, J G; Daum, K; Semes, L; Wisniewski, J; Rutstein, R; Alexander, L; Beisel, J; Mann, K; Nawakowski, R; Smith, M; Bartolucci, A

    1996-02-01

    The relationship between eye dominance and batting skill in baseball has been investigated, but conflicting results have been obtained. In addition, little attention has been given to the relationship, if any, between eye dominance and fielding and pitching skill. A vision screening of 215 professional baseball players in the Southern Baseball League was performed and the eye dominance of these players was determined by a sighting test. Handedness for batting, fielding, and pitching was determined by history. The screening revealed that 66 percent of players were right-eye dominant and that, of 92 players who met the criteria established to qualify for the league batting championship, 60 percent had matched dominance of eye and hand. When official league batting averages were obtained for these 92 players, it was found that there was no statistically significant difference between batters with matched dominance (.278 mean batting average). For the 149 fielders in the league, no statistically significant differences based on eye dominance were found for fielding average (.893 matched dominance, .864 crossed dominance); for the 89 pitchers, a similar result was obtained. Pitchers were also evaluated with respect to eye dominance and earned run average, but no significant difference was found (3.91 matched dominance, 4.03 crossed dominance). Results indicate that there is no association between eye dominance, and hitting, fielding, or pitching skill in baseball.

  8. The Hands with Eyes and Nose in the Palm: As Effective Communication Alternatives for Profoundly Deaf People in Zimbabwe

    ERIC Educational Resources Information Center

    Mutswanga, Phillipa

    2017-01-01

    Drawing from the experiences and testimonies of people with profound deafness, the study qualitatively explored the use of the hands with eyes and nose in the palm as communication alternatives in the field of deafness. The study was prompted by the 27 year old lady, Leah Katz-Hernandez who is deaf who got engaged in March 2015 as the 2016…

  9. HotEye (tm) Based Coordinate Measuring Machine for Forging Industry

    SciTech Connect

    OG Technologies

    2003-06-09

    The objective of this project is to develop a 3 dimensional measurement system for the domestic forging industry based on HotEye{trademark}. This technology will allow high definition camera to accurately image a red hot object. The project marries conventional Coordinate Measurement Machine ''CMM'' technology to HotEye{trademark} technology to permit the accurate measurement of forged parts while they are at high temperature. Being able to take such measurements will dramatically reduce the amount of scrap produced by the domestic forging industry. This industry wastes a significant amount of energy because of the high rate of scrap it produces. OGT will: (1) Develop a 3D measurement sensor head that will work on a part at a temperature up to 1,450 C with an accuracy of 0.1mm or better and with a scanning speed of less than 10 seconds for an area of 100mm x 100mm. (2) Develop a Virtual-Fixturing software package to alleviate the need of precise hard fixturing. (3) Integrate the 3D measurement sensor head and the Virtual-Fixturing software into a standard CMM, both hardware (replacing the probes) and software (data format and user interface match) so that the system can automatically perform a complete preprogrammed measurement of a hot product. (4) Test and evaluate the system in a forging facility.

  10. Ebbinghaus figures that deceive the eye do not necessarily deceive the hand.

    PubMed

    Knol, Hester; Huys, Raoul; Sarrazin, Jean-Christophe; Spiegler, Andreas; Jirsa, Viktor K

    2017-06-08

    In support of the visual stream dissociation hypothesis, which states that distinct visual streams serve vision-for-perception and vision-for-action, visual size illusions were reported over 20 years ago to 'deceive the eye but not the hand'. Ever since, inconclusive results and contradictory interpretations have accumulated. Therefore, we investigated the effects of the Ebbinghaus figure on repetitive aiming movements with distinct dynamics. Participants performed a Fitts' task in which Ebbinghaus figures served as targets. We systematically varied the three parameters which have been shown to influence the perceived size of the Ebbinghaus figure's target circle, namely the size of the target, its distance to the context circles and the size of the context circles. This paper shows that movement is significantly affected by the context size, but, in contrast to perception, not by the other two parameters. This is especially prominent in the approach phase of the movement towards the target, regardless of the dynamics. To reconcile the findings, we argue that different informational variables are used for size perception and the visual control of movements irrespective of whether certain variables induce (perceptual) illusions.

  11. Real Time Eye Tracking and Hand Tracking Using Regular Video Cameras for Human Computer Interaction

    DTIC Science & Technology

    2011-01-01

    gaze estimation , we have developed a novel eye tracking and 3D eyeball based gaze estimation approach in a non - intrusive way without using special...Processing, Volume 2007, Issue 3, Article No. 4, 2007. [40] Yoo, D.H. and Chung, M.J., “A Novel Non - Intrusive Eye Gaze Estimation using Cross-Ratio...and eyeball estimation were implemented, including a new model for eye gaze estimation and eye

  12. Pilot Study: The Role of the Hemispheric Lateralization in Mental Disorders by Use of the Limb (Eye, Hand, Foot) Dominance.

    PubMed

    Goodarzi, Naser; Dabbaghi, Parviz; Valipour, Habib; Vafadari, Behnam

    2015-04-01

    Based on the previous studies, we know that the hemispheric lateralization defects, increase the probability of psychological disorders. We also know that dominant limb is controlled by dominant hemisphere and limb preference is used as an indicator for hemisphere dominance. In this study we attempted to explore the hemispheric dominance by the use of three limbs (hand, foot and eye). We performed this survey on two samples, psychiatric patients compared with normal population. For this purpose, knowing that the organ dominance is stabilized in adolescence, and age has no effect on the people above 15, we used 48 high school girls and 65 boys as the final samples of normal population. The patient group included 57 male and 26 female who were chronic psychiatric patients. The result shows that left-eye dominance is more in patients than the normal group (P=0.000) but the handedness and footedness differences are not significance. In psychotic, bipolar and depressive disorders, eye dominance had significant difference (P=0.018). But this is not true about hand and foot dominance. Our findings proved that generally in psychiatric patients, left-eye dominance is more common, left-eye dominance is also more in psychotic and depressive disorders. It is less common in bipolar disorders.

  13. Pilot Study: The Role of the Hemispheric Lateralization in Mental Disorders by Use of the Limb (Eye, Hand, Foot) Dominance

    PubMed Central

    Goodarzi, Naser; Dabbaghi, Parviz; Valipour, Habib; Vafadari, Behnam

    2015-01-01

    Introduction: Based on the previous studies, we know that the hemispheric lateralization defects, increase the probability of psychological disorders. We also know that dominant limb is controlled by dominant hemisphere and limb preference is used as an indicator for hemisphere dominance. In this study we attempted to explore the hemispheric dominance by the use of three limbs (hand, foot and eye). Methods: We performed this survey on two samples, psychiatric patients compared with normal population. For this purpose, knowing that the organ dominance is stabilized in adolescence, and age has no effect on the people above 15, we used 48 high school girls and 65 boys as the final samples of normal population. The patient group included 57 male and 26 female who were chronic psychiatric patients. Results: The result shows that left-eye dominance is more in patients than the normal group (P=0.000) but the handedness and footedness differences are not significance. In psychotic, bipolar and depressive disorders, eye dominance had significant difference (P=0.018). But this is not true about hand and foot dominance. Discussion: Our findings proved that generally in psychiatric patients, left-eye dominance is more common, left-eye dominance is also more in psychotic and depressive disorders. It is less common in bipolar disorders. PMID:27307954

  14. Review and Evaluation of Hand–Arm Coordinate Systems for Measuring Vibration Exposure, Biodynamic Responses, and Hand Forces

    PubMed Central

    Dong, Ren G.; Sinsel, Erik W.; Welcome, Daniel E.; Warren, Christopher; Xu, Xueyan S.; McDowell, Thomas W.; Wu, John Z.

    2015-01-01

    The hand coordinate systems for measuring vibration exposures and biodynamic responses have been standardized, but they are not actually used in many studies. This contradicts the purpose of the standardization. The objectives of this study were to identify the major sources of this problem, and to help define or identify better coordinate systems for the standardization. This study systematically reviewed the principles and definition methods, and evaluated typical hand coordinate systems. This study confirms that, as accelerometers remain the major technology for vibration measurement, it is reasonable to standardize two types of coordinate systems: a tool-based basicentric (BC) system and an anatomically based biodynamic (BD) system. However, these coordinate systems are not well defined in the current standard. Definition of the standard BC system is confusing, and it can be interpreted differently; as a result, it has been inconsistently applied in various standards and studies. The standard hand BD system is defined using the orientation of the third metacarpal bone. It is neither convenient nor defined based on important biological or biodynamic features. This explains why it is rarely used in practice. To resolve these inconsistencies and deficiencies, we proposed a revised method for defining the realistic handle BC system and an alternative method for defining the hand BD system. A fingertip-based BD system for measuring the principal grip force is also proposed based on an important feature of the grip force confirmed in this study. PMID:26929824

  15. Hand washing induces a clean slate effect in moral judgments: a pupillometry and eye-tracking study.

    PubMed

    Kaspar, Kai; Krapp, Vanessa; König, Peter

    2015-05-21

    Physical cleansing is commonly understood to protect us against physical contamination. However, recent studies showed additional effects on moral judgments. Under the heading of the "Macbeth effect" direct links between bodily cleansing and one's own moral purity have been demonstrated. Here we investigate (1) how moral judgments develop over time and how they are altered by hand washing, (2) whether changes in moral judgments can be explained by altered information sampling from the environment, and (3) whether hand washing affects emotional arousal. Using a pre-post control group design, we found that morality ratings of morally good and bad scenes acquired more extreme values in the control group over time, an effect that was fully counteracted by intermediate hand washing. This result supports the notion of a clean slate effect by hand washing. Thereby, eye-tracking data did not uncover differences in eye movement behavior that may explain differences in moral judgments. Thus, the clean slate effect is not due to altered information sampling from the environment. Finally, compared to the control group, pupil diameter decreased after hand washing, thus demonstrating a direct physiological effect. The results shed light on the physiological mechanisms behind this type of embodiment phenomenon.

  16. Hand Washing Induces a Clean Slate Effect in Moral Judgments: A Pupillometry and Eye-Tracking Study

    PubMed Central

    Kaspar, Kai; Krapp, Vanessa; König, Peter

    2015-01-01

    Physical cleansing is commonly understood to protect us against physical contamination. However, recent studies showed additional effects on moral judgments. Under the heading of the “Macbeth effect” direct links between bodily cleansing and one’s own moral purity have been demonstrated. Here we investigate (1) how moral judgments develop over time and how they are altered by hand washing, (2) whether changes in moral judgments can be explained by altered information sampling from the environment, and (3) whether hand washing affects emotional arousal. Using a pre-post control group design, we found that morality ratings of morally good and bad scenes acquired more extreme values in the control group over time, an effect that was fully counteracted by intermediate hand washing. This result supports the notion of a clean slate effect by hand washing. Thereby, eye-tracking data did not uncover differences in eye movement behavior that may explain differences in moral judgments. Thus, the clean slate effect is not due to altered information sampling from the environment. Finally, compared to the control group, pupil diameter decreased after hand washing, thus demonstrating a direct physiological effect. The results shed light on the physiological mechanisms behind this type of embodiment phenomenon. PMID:25994083

  17. Are two hands (from different people) better than one? Mode effects and differential transfer between manual coordination modes.

    PubMed

    Gorman, Jamie C; Crites, Michael J

    2013-08-01

    We report an experiment in which we investigated differential transfer between unimanual (one-handed), bimanual (two-handed), and intermanual (different peoples' hands) coordination modes. People perform some manual tasks faster than others ("mode effects"). However, little is known about transfer between coordination modes. To investigate differential transfer, we draw hypotheses from two perspectives--information based and constraint based--of bimanual and interpersonal coordination and skill acquisition. Participants drove a teleoperated rover around a circular path in sets of two 2-min trials using two of the different coordination modes. Speed and variability of the rover's path were measured. Order of coordination modes was manipulated to examine differential transfer and mode effects. Differential transfer analyses revealed patterns of positive transfer from simpler (localized spatiotemporal constraints) to more complex (distributed spatiotemporal constraints) coordination modes paired with negative transfer in the opposite direction. Mode effects indicated that intermanual performance was significantly faster than unimanual performance, and bimanual performance was intermediate. Importantly, all of these effects disappeared with practice. The observed patterns of differential transfer between coordination modes may be better accounted for by a constraint-based explanation of differential transfer than by an information-based one. Mode effects may be attributable to anticipatory movements based on dyads' access to mutual visual information. Although people may be faster using more-complex coordination modes, when operators transition between modes, they may be more effective transitioning from simpler (e.g., bimanual) to more complex (e.g., intermanual) modes than vice versa. However, this difference may be critical only for novel or rarely practiced tasks.

  18. Effect of input devices on eye-hand coordination in young children.

    PubMed

    Naido, R; Salkind, N J

    1990-06-01

    While preschoolers' practice for 4 10- to 15-min. periods each week for 6 wk. on a computerized maze using a mouse increased scores over those of a control group, there was no generalization to a paper-and-pencil task. Pre- and posttest scores on the Frostig Test of Visual Perception differed significantly, although boys and girls scored similarly.

  19. Double-coding test: a new paper-and-pencil measure of eye-hand coordination.

    PubMed

    Lufi, D

    2001-06-01

    The present research presents the development of a new paper-and-pencil coding task that may find a variety of uses in the psychological assessment of cognitive processes. The aim of the new test, named the Double-coding Test, was to create a more complex task than the previous coding tests. This new task requires two different coding processes before marking the correct sign in the appropriate space. To validate this new double-coding task it was administered along with the Coding B subtest of the Wechsler Intelligence Scale for Children-Revised and the d2 Test. Also for validation the new test was administered to a clinical group of children having Attention Deficit/Hyperactivity Disorder. A sample of normal children is presented for five different ages from 8 and 13 years. Analysis showed that the Double-coding Test differentiates between clinical group and normal children more effectively than does the WISC-R Coding B subtest or the d2 Test. Suggestions are offered for use of the Double-coding Test.

  20. Eye movements are coordinated with pectoral fin beats during locomotion in a marine teleost fish.

    PubMed

    Mandecki, Joanna L; Domenici, Paolo

    2015-04-15

    Animals must simultaneously engage multiple functional systems in order to navigate, feed and survive in complex environments. Nearly all vertebrates perform rapid gaze-shifting eye movements called saccades, but we know little about the behaviour of saccades during rhythmic locomotion. This study examined how saccades are coordinated with locomotor movements in a pectoral-fin-propelled teleost fish, Cymatogaster aggregata, the shiner surfperch. Individual fish were filmed swimming in a flow tank at 10 cm s(-1), and timing data were analysed using circular statistics. The results reveal that C. aggregata generates saccades non-uniformly throughout the pectoral fin cycle. Saccades primarily occur during fin abduction, when a large amount of thrust is produced, and rarely occur during the thrust-free refractory phase. Because vision is known to be impaired during saccades, we hypothesize that C. aggregata synchronizes saccades with periods of high acceleration in order to stabilize retinal images during low-acceleration phases, which are nearly saccade-free.

  1. Gaze Behavior in One-Handed Catching and Its Relation with Interceptive Performance: What the Eyes Can't Tell

    PubMed Central

    Cesqui, Benedetta; Mezzetti, Maura; Lacquaniti, Francesco; d'Avella, Andrea

    2015-01-01

    In ball sports, it is usually acknowledged that expert athletes track the ball more accurately than novices. However, there is also evidence that keeping the eyes on the ball is not always necessary for interception. Here we aimed at gaining new insights on the extent to which ocular pursuit performance is related to catching performance. To this end, we analyzed eye and head movements of nine subjects catching a ball projected by an actuated launching apparatus. Four different ball flight durations and two different ball arrival heights were tested and the quality of ocular pursuit was characterized by means of several timing and accuracy parameters. Catching performance differed across subjects and depended on ball flight characteristics. All subjects showed a similar sequence of eye movement events and a similar modulation of the timing of these events in relation to the characteristics of the ball trajectory. On a trial-by-trial basis there was a significant relationship only between pursuit duration and catching performance, confirming that keeping the eyes on the ball longer increases catching success probability. Ocular pursuit parameters values and their dependence on flight conditions as well as the eye and head contributions to gaze shift differed across subjects. However, the observed average individual ocular behavior and the eye-head coordination patterns were not directly related to the individual catching performance. These results suggest that several oculomotor strategies may be used to gather information on ball motion, and that factors unrelated to eye movements may underlie the observed differences in interceptive performance. PMID:25793989

  2. Major review: ocular sighting dominance: a review and a study of athletic proficiency and eye-hand dominance in a collegiate baseball team.

    PubMed

    Portal, J M; Romano, P E

    1998-01-01

    Laterality preference in sensory and motor functions of symmetrically disposed organisms have been studied for centuries. The relation between handedness and the eyes and vision (ocular sighting dominance) has been a focal point despite their physiologic dissimilarity. To examine a college varsity baseball team for handedness and ocular sighting dominance to determine if their patterns of eye-hand dominance differed from the normal population and/or contributed to their individual relative success compared to their peers. Specifically: whether crossed eye- hand dominance favors the batter and uncrossed eye-hand dominance favors the pitcher. Twenty five UF varsity players were examined. All were male. Their visual acuity, stereoscopic vision, ocular motility and ocular sighting dominance were determined, the last by a pointing test which allowed the diagnosis of a central form of ocular dominance, but was not per se affected by handedness. Handedness was determined by preferred arm for throwing or hitting. No subject was ambidextrous. A control population was established consisting of the first 100 consecutive adults seen by the first author in the UF Eye Center with 20/20 vision O.U. and a normal eye exam. The control group displayed eye-hand dominance patterns similar to those previously reported in the literature for the general population. In the experimental group of baseball players, the incidence of conventionally predominant (in normals) ipsilateral or uncrossed eye-hand dominance was much lower (39%) than the normal control population (65%). The incidence of contralateral or crossed eye- hand dominance was 35%, twice that of the normal control population (18%) (p<0.01). The incidence of central ocular dominance with right or left handedness was 26% or 50% higher than a normal control population (17%) (p<0.25). With regard to individual performance, those players with central ocular dominance, whether right or left handed, were the most successful players in

  3. Contrasting speed-accuracy tradeoffs for eye and hand movements reveal the optimal nature of saccade kinematics.

    PubMed

    Gopal, Atul; Jana, Sumitash; Murthy, Aditya

    2017-09-01

    In contrast to hand movements, the existence of a neural representation of saccade kinematics is unclear. Saccade kinematics is typically thought to be specified by motor error/desired displacement and generated by brain stem circuits that are not penetrable to voluntary control. We studied the influence of instructed hand movement velocity on the kinematics of saccades executed without explicit instructions. When the hand movement was slow the saccade velocity decreased, independent of saccade amplitude. We leveraged this modulation of saccade velocity to study the optimality of saccades (in terms of velocity and endpoint accuracy) in relation to the well-known speed-accuracy tradeoff that governs voluntary movements (Fitts' law). In contrast to hand movements that obeyed Fitts' law, normometric saccades exhibited the greatest endpoint accuracy and lower reaction times, relative to saccades accompanying slow and fast hand movements. In the slow condition, where saccade endpoint accuracy suffered, we observed that targets were more likely to be foveated by two saccades resulting in step-saccades. Interestingly, the endpoint accuracy was higher in two-saccade trials, compared with one-saccade trials in both the slow and fast conditions. This indicates that step-saccades are a part of the kinematic plan for optimal control of endpoint accuracy. Taken together, these findings suggest normometric saccades are already optimized to maximize endpoint accuracy and the modulation of saccade velocity by hand velocity is likely to reflect the sharing of kinematic plans between the two effectors.NEW & NOTEWORTHY The optimality of saccade kinematics has been suggested by modeling studies but experimental evidence is lacking. However, we observed that, when subjects voluntarily modulated their hand velocity, the velocity of saccades accompanying these hand movements was also modulated, suggesting a shared kinematic plan for eye and hand movements. We leveraged this modulation to

  4. Carrying a rifle with both hands affects upper body transverse plane kinematics and pelvis-trunk coordination.

    PubMed

    Seay, Joseph F; Hasselquist, Leif; Bensel, Carolyn K

    2011-02-01

    The purpose of this study was to assess how carrying a rifle in both hands affects upper body motion and coordination during locomotion. In total, 11 male soldiers walked (1.34 m/s) and ran (2.46 m/s) with a weapon (M4 condition) and without a weapon (NW condition) while kinematic pelvis and trunk data were collected. Two-way ANOVA was used to compare segmental ranges of motion (ROM), pelvis-trunk coordination (continuous relative phase) and coordination variability between gait mode and weapon combinations. Carrying a weapon decreased sagittal plane trunk ROM at both speeds and increased trunk rotation during running. Mean (±SD) transverse plane coordination was more in-phase while carrying a weapon (M4 = 83°±31, NW = 60°±36, p = 0.027) and transverse plane coordination variability decreased (M4 = 23°±3.6, NW = 15°±4.4, p = 0.043). Coordination differences between M4 and NW were similar to differences reported in the literature between individuals with and without back pain. Long-term injury implications due to decreased coordination variability are discussed. STATEMENT OF RELEVANCE: Knowledge of the effects of rifle carriage on pelvis-trunk coordination may provide insight into short-term protective strategies and long-term injury mechanisms. These should be considered in occupations requiring individuals to carry torso loads in combination with holding an object in both hands that restricts arm swing.

  5. Influence of Fatigue on Hand Muscle Coordination and EMG-EMG Coherence During Three-Digit Grasping

    PubMed Central

    Danna-Dos Santos, Alessander; Poston, Brach; Jesunathadas, Mark; Bobich, Lisa R.; Hamm, Thomas M.

    2010-01-01

    Fingertip force control requires fine coordination of multiple hand muscles within and across the digits. While the modulation of neural drive to hand muscles as a function of force has been extensively studied, much less is known about the effects of fatigue on the coordination of simultaneously active hand muscles. We asked eight subjects to perform a fatiguing contraction by gripping a manipulandum with thumb, index, and middle fingers while matching an isometric target force (40% maximal voluntary force) for as long as possible. The coordination of 12 hand muscles was quantified as electromyographic (EMG) muscle activation pattern (MAP) vector and EMG-EMG coherence. We hypothesized that muscle fatigue would cause uniform changes in EMG amplitude across all muscles and an increase in EMG-EMG coherence in the higher frequency bands but with an invariant heterogeneous distribution across muscles. Muscle fatigue caused a 12.5% drop in the maximum voluntary contraction force (P < 0.05) at task failure and an increase in the SD of force (P < 0.01). Although EMG amplitude of all muscles increased during the fatiguing contraction (P < 0.001), the MAP vector orientation did not change, indicating that a similar muscle coordination pattern was used throughout the fatiguing contraction. Last, EMG-EMG coherence (0–35 Hz) was significantly greater at the end than at the beginning of the fatiguing contraction (P < 0.01) but was heterogeneously distributed across hand muscles. These findings suggest that similar mechanisms are involved for modulating and sustaining digit forces in nonfatiguing and fatiguing contractions, respectively. PMID:20926609

  6. Influence of fatigue on hand muscle coordination and EMG-EMG coherence during three-digit grasping.

    PubMed

    Danna-Dos Santos, Alessander; Poston, Brach; Jesunathadas, Mark; Bobich, Lisa R; Hamm, Thomas M; Santello, Marco

    2010-12-01

    Fingertip force control requires fine coordination of multiple hand muscles within and across the digits. While the modulation of neural drive to hand muscles as a function of force has been extensively studied, much less is known about the effects of fatigue on the coordination of simultaneously active hand muscles. We asked eight subjects to perform a fatiguing contraction by gripping a manipulandum with thumb, index, and middle fingers while matching an isometric target force (40% maximal voluntary force) for as long as possible. The coordination of 12 hand muscles was quantified as electromyographic (EMG) muscle activation pattern (MAP) vector and EMG-EMG coherence. We hypothesized that muscle fatigue would cause uniform changes in EMG amplitude across all muscles and an increase in EMG-EMG coherence in the higher frequency bands but with an invariant heterogeneous distribution across muscles. Muscle fatigue caused a 12.5% drop in the maximum voluntary contraction force (P < 0.05) at task failure and an increase in the SD of force (P < 0.01). Although EMG amplitude of all muscles increased during the fatiguing contraction (P < 0.001), the MAP vector orientation did not change, indicating that a similar muscle coordination pattern was used throughout the fatiguing contraction. Last, EMG-EMG coherence (0-35 Hz) was significantly greater at the end than at the beginning of the fatiguing contraction (P < 0.01) but was heterogeneously distributed across hand muscles. These findings suggest that similar mechanisms are involved for modulating and sustaining digit forces in nonfatiguing and fatiguing contractions, respectively.

  7. Eye-Hand Synergy and Intermittent Behaviors during Target-Directed Tracking with Visual and Non-visual Information

    PubMed Central

    Huang, Chien-Ting; Hwang, Ing-Shiou

    2012-01-01

    Visual feedback and non-visual information play different roles in tracking of an external target. This study explored the respective roles of the visual and non-visual information in eleven healthy volunteers who coupled the manual cursor to a rhythmically moving target of 0.5 Hz under three sensorimotor conditions: eye-alone tracking (EA), eye-hand tracking with visual feedback of manual outputs (EH tracking), and the same tracking without such feedback (EHM tracking). Tracking error, kinematic variables, and movement intermittency (saccade and speed pulse) were contrasted among tracking conditions. The results showed that EHM tracking exhibited larger pursuit gain, less tracking error, and less movement intermittency for the ocular plant than EA tracking. With the vision of manual cursor, EH tracking achieved superior tracking congruency of the ocular and manual effectors with smaller movement intermittency than EHM tracking, except that the rate precision of manual action was similar for both types of tracking. The present study demonstrated that visibility of manual consequences altered mutual relationships between movement intermittency and tracking error. The speed pulse metrics of manual output were linked to ocular tracking error, and saccade events were time-locked to the positional error of manual tracking during EH tracking. In conclusion, peripheral non-visual information is critical to smooth pursuit characteristics and rate control of rhythmic manual tracking. Visual information adds to eye-hand synchrony, underlying improved amplitude control and elaborate error interpretation during oculo-manual tracking. PMID:23236498

  8. Hand Ground Nanoscale Zn(II)-Coordination Polymers Derived from NSAIDs: Cell Migration Inhibition of Human Breast Cancer Cells.

    PubMed

    Dastidar, Parthasarathi; Paul, Mithun; Sarkar, Koushik; Deb, Jolly

    2017-02-25

    Increased level of intracellular prostaglandin E2 (PGE2) has been linked with the unregulated cancer cell migration that often leads to metastasis. Non-steroidal-anti-inflammatory-drugs (NSAIDs) are known inhibitors of cyclooxygenase (COX) enzymes responsible for increased PGE2 concentration in inflammated as well as cancer cells. In this article, we demonstrated that NSAID derived Zn(II)-coordination polymers were able to inhibit cell migration of human breast cancer cells. Various NSAIDs were anchored to a series of 1D Zn(II)-coordination polymers via carboxylate-Zn coordination and fully characterized by single crystal X-ray diffraction. Hand grinding in laboratory mortar and pastel resulted in nano-scale coordination polymers, for the first time, suitable for biological studies. Two such hand ground nano-scale coordination polymers namely NCP1a and NCP2a containing naproxen (a well-studied NSAID) were successfully internalized within the human breast cancer cells MDA-MD-231 as evident from cellular imaging using fluorescence microscope, were able to kill the cancer cells (MTT assay) more efficiently than the corresponding mother drug naproxen and most importantly inhibited significantly the cancer cell migration thereby displaying anti-cancer activity.

  9. Hand-Camera Coordination Varies over Time in Users of the Argus® II Retinal Prosthesis System

    PubMed Central

    Barry, Michael P.; Dagnelie, Gislin

    2016-01-01

    multivariate analysis of variance (MANOVA)), up to 21–29° within subjects over the observed period. Across subjects, optimal CAPs showed an average rate of change of 0.39°/day (SD 0.36°/day). Conclusions: Optimal CAPs varied dramatically over time for all subjects. Subjects displayed no adaptation to misaligned CAPs without feedback. Regular recalibration of CAPs may be required to maintain hand-camera coordination. PMID:27199689

  10. Hand-Camera Coordination Varies over Time in Users of the Argus(®) II Retinal Prosthesis System.

    PubMed

    Barry, Michael P; Dagnelie, Gislin

    2016-01-01

    to 21-29° within subjects over the observed period. Across subjects, optimal CAPs showed an average rate of change of 0.39°/day (SD 0.36°/day). Optimal CAPs varied dramatically over time for all subjects. Subjects displayed no adaptation to misaligned CAPs without feedback. Regular recalibration of CAPs may be required to maintain hand-camera coordination.

  11. Helping Hands: A World of Manipulatives To Boost Handwriting Skills.

    ERIC Educational Resources Information Center

    Naus, June M.

    2000-01-01

    This article identifies possible causes of handwriting difficulties and suggests activities to facilitate the development of hand muscles and handwriting skills. It discusses handwriting readiness, wrist stability, hand development activities, pencil grasp, hand dominance, eye-hand coordination, basic strokes, general readiness skills, writing…

  12. Helping Hands: A World of Manipulatives To Boost Handwriting Skills.

    ERIC Educational Resources Information Center

    Naus, June M.

    2000-01-01

    This article identifies possible causes of handwriting difficulties and suggests activities to facilitate the development of hand muscles and handwriting skills. It discusses handwriting readiness, wrist stability, hand development activities, pencil grasp, hand dominance, eye-hand coordination, basic strokes, general readiness skills, writing…

  13. Movement Coordination in Psychotherapy: Synchrony of Hand Movements is Associated with Session Outcome. A Single-Case Study.

    PubMed

    Ramseyer, Fabian; Tschacher, Wolfgang

    2016-04-01

    Previous work has shown that nonverbal behavior was associated with both session-level outcome and global outcome in psychotherapy. Nonverbal synchrony--here the coordination between patient's and psychotherapist's movement behavior--is a facet of nonverbal behavior that has recently been studied with video-based motion energy analysis (MEA). The present study aimed to replicate and extend these findings by using direct acquisition of movement data. In a single-case analysis, we monitored patient's and therapist's hand movements with a high-resolution accelerometric measurement system (Vitaport (r)). In addition to these behavioral data, both patient and therapist provided session-level ratings of various factors relevant to the psychotherapy process, which were assessed with post-session questionnaires. The patient-therapist coordination of hand movements, i.e. nonverbal synchrony, in (N = 27) sessions of this dyadic psychotherapy was positively associated with progress reported in post-session questionnaires. Sessions with good evaluations concerning the quality of therapeutic alliance were characterized by high movement coordination. Thus, accelerometric data of this therapy dyad confirmed previous findings gained through video analyses: The coordination of nonverbal behavior shown by patient and therapist was an indicator of beneficial processes occurring within sessions. This replication study showed that nonverbal synchrony embodies important aspects of the alliance. Its assessment and quantification may provide therapists important additional information on processes that usually occur outside conscious awareness, but that nevertheless influence core aspects of the therapy.

  14. Design and characterization of the OpenWrist: A robotic wrist exoskeleton for coordinated hand-wrist rehabilitation.

    PubMed

    Pezent, Evan; Rose, Chad G; Deshpande, Ashish D; O'Malley, Marcia K

    2017-07-01

    Robotic devices have been clinically verified for use in long duration and high intensity rehabilitation needed for motor recovery after neurological injury. Targeted and coordinated hand and wrist therapy, often overlooked in rehabilitation robotics, is required to regain the ability to perform activities of daily living. To this end, a new coupled hand-wrist exoskeleton has been designed. This paper details the design of the wrist module and several human-related considerations made to maximize its potential as a coordinated hand-wrist device. The serial wrist mechanism has been engineered to facilitate donning and doffing for impaired subjects and to insure compatibility with the hand module in virtual and assisted grasping tasks. Several other practical requirements have also been addressed, including device ergonomics, clinician-friendliness, and ambidextrous reconfigurability. The wrist module's capabilities as a rehabilitation device are quantified experimentally in terms of functional workspace and dynamic properties. Specifically, the device possesses favorable performance in terms of range of motion, torque output, friction, and closed-loop position bandwidth when compared with existing devices. The presented wrist module's performance and operational considerations support its use in a wide range of future clinical investigations.

  15. Head-Eye Coordination Increases with Age and Varies across Countries

    PubMed Central

    Poirier, Frédéric J.A.M.; Giraudet, Guillaume; Faubert, Jocelyn

    2015-01-01

    ABSTRACT Purpose Head movements in older people may contribute to their dizziness and equilibrium problems. Head gain is the ratio of head movement to total movement (head + eye) when executing a saccade to an eccentric target. Two studies have investigated the relationship between head gain and age but have provided conflicting results. Methods We report head gain data collected from research laboratories and optician stores. Our sample sizes are much larger (n = 657 for laboratory, n = 64,458 for optician stores), permitting more detailed analyses. Results The head-eye coefficient, expressed as 100 times the square root of head gain, was bimodal with one mode of primarily eye movers and one mode of eye-and-head movers. Head-eye coefficient increased with age and was invariant with eye correction and gender. We also found an effect of nation that seemed associated with gross domestic product or by latitude (in the northern hemisphere) and log population density. Discussion Assuming that head movements and visual distortions contribute to dizziness and equilibrium problems, our study suggests that customizing eyewear based on age and country may help in reducing the prevalence of problems associated with head and/or eye movements. PMID:26421683

  16. Control Model for Dampening Hand Vibrations Using Information of Internal and External Coordinates

    PubMed Central

    Togo, Shunta; Kagawa, Takahiro; Uno, Yoji

    2015-01-01

    In the present study, we investigate a control mechanism that dampens hand vibrations. Here, we propose a control method with two components to suppress hand vibrations. The first is a passive suppression method that lowers the joint stiffness to passively dampen the hand vibrations. The second is an active suppression method that adjusts an equilibrium point based on skyhook control to actively dampen the hand vibrations. In a simulation experiment, we applied these two methods to dampen hand vibrations during the shoulder’s horizontal oscillation. We also conducted a measurement experiment wherein a subject’s shoulder was sinusoidally oscillated by a platform that generated horizontal oscillations. The results of the measurement experiments showed that the jerk of each part of the arm in a task using a cup filled with water was smaller than the shoulder jerk and that in a task with a cup filled with stones was larger than the shoulder jerk. Moreover, the amplitude of the hand trajectory in both horizontal and vertical directions was smaller in a task using a cup filled with water than in a task using a cup filled with stones. The results of the measurement experiments were accurately reproduced by the active suppression method based on skyhook control. These results suggest that humans dampen hand vibrations by controlling the equilibrium point through the information of the external workspace and the internal body state rather than by lowering joint stiffness only by using internal information. PMID:25876037

  17. Control model for dampening hand vibrations using information of internal and external coordinates.

    PubMed

    Togo, Shunta; Kagawa, Takahiro; Uno, Yoji

    2015-01-01

    In the present study, we investigate a control mechanism that dampens hand vibrations. Here, we propose a control method with two components to suppress hand vibrations. The first is a passive suppression method that lowers the joint stiffness to passively dampen the hand vibrations. The second is an active suppression method that adjusts an equilibrium point based on skyhook control to actively dampen the hand vibrations. In a simulation experiment, we applied these two methods to dampen hand vibrations during the shoulder's horizontal oscillation. We also conducted a measurement experiment wherein a subject's shoulder was sinusoidally oscillated by a platform that generated horizontal oscillations. The results of the measurement experiments showed that the jerk of each part of the arm in a task using a cup filled with water was smaller than the shoulder jerk and that in a task with a cup filled with stones was larger than the shoulder jerk. Moreover, the amplitude of the hand trajectory in both horizontal and vertical directions was smaller in a task using a cup filled with water than in a task using a cup filled with stones. The results of the measurement experiments were accurately reproduced by the active suppression method based on skyhook control. These results suggest that humans dampen hand vibrations by controlling the equilibrium point through the information of the external workspace and the internal body state rather than by lowering joint stiffness only by using internal information.

  18. Eye-head coordination in the guinea pig I. Responses to passive whole-body rotations.

    PubMed

    Shanidze, N; Kim, A H; Raphael, Y; King, W M

    2010-09-01

    Vestibular reflexes act to stabilize the head and eyes in space during locomotion. Head stability is essential for postural control, whereas retinal image stability enhances visual acuity and may be essential for an animal to distinguish self-motion from that of an object in the environment. Guinea pig eye and head movements were measured during passive whole-body rotation in order to assess the efficacy of vestibular reflexes. The vestibulo-ocular reflex (VOR) produced compensatory eye movements with a latency of approximately 7 ms that compensated for 46% of head movement in the dark and only slightly more in the light (54%). Head movements, in response to abrupt body rotations, also contributed to retinal stability (21% in the dark; 25% in the light) but exhibited significant variability. Although compensatory eye velocity produced by the VOR was well correlated with head-in-space velocity, compensatory head-on-body speed and direction were variable and poorly correlated with body speed. The compensatory head movements appeared to be determined by passive biomechanical (e.g., inertial effects, initial tonus) and active mechanisms (the vestibulo-collic reflex or VCR). Chemically induced, bilateral lesions of the peripheral vestibular system abolished both compensatory head and eye movement responses.

  19. Eye - head coordination in the guinea pig I. Responses to passive whole body rotations

    PubMed Central

    Shanidze, N.; Kim, A. H.; Raphael, Y.; King, W. M.

    2010-01-01

    Vestibular reflexes act to stabilize the head and eyes in space during locomotion. Head stability is essential for postural control whereas retinal image stability enhances visual acuity and may be essential for an animal to distinguish self-motion from that of an object in the environment. Guinea pig eye and head movements were measured during passive whole body rotation in order to assess the efficacy of vestibular reflexes. The vestibulo-ocular reflex (VOR) produced compensatory eye movements with a latency of ~7 msec that compensated for 46% of head movement in the dark and only slightly more in the light (54%). Head movements, in response to abrupt body rotations, also contributed to retinal stability (21% in the dark; 25% in the light) but exhibited significant variability. Although compensatory eye velocity produced by the VOR was well correlated with head-in-space velocity, compensatory head-on-body speed and direction were variable and poorly correlated with body speed. The compensatory head movements appeared to be determined by passive biomechanical (e.g., inertial effects, initial tonus) and active mechanisms (the vestibulo-collic reflex or VCR). Chemically induced, bilateral lesions of the peripheral vestibular system abolished both compensatory head and eye movement responses. PMID:20686891

  20. Give me a sign: decoding complex coordinated hand movements using high-field fMRI.

    PubMed

    Bleichner, Martin G; Jansma, Johan M; Sellmeijer, Jim; Raemaekers, Mathijs; Ramsey, Nicolas F

    2014-03-01

    Decoding movements from the human cortex has been a topic of great interest for controlling an artificial limb in non-human primates and severely paralyzed people. Here we investigate feasibility of decoding gestures from the sensorimotor cortex in humans, using 7 T fMRI. Twelve healthy volunteers performed four hand gestures from the American Sign Language Alphabet. These gestures were performed in a rapid event related design used to establish the classifier and a slow event-related design, used to test the classifier. Single trial patterns were classified using a pattern-correlation classifier. The four hand gestures could be classified with an average accuracy of 63 % (range 35–95 %), which was significantly above chance (25 %). The hand region was, as expected, the most active region, and the optimal volume for classification was on average about 200 voxels, although this varied considerably across individuals. Importantly, classification accuracy correlated significantly with consistency of gesture execution. The results of our study demonstrate that decoding gestures from the hand region of the sensorimotor cortex using 7 T fMRI can reach very high accuracy, provided that gestures are executed in a consistent manner. Our results further indicate that the neuronal representation of hand gestures is robust and highly reproducible. Given that the most active foci were located in the hand region, and that 7 T fMRI has been shown to agree with electrocorticography, our results suggest that this confined region could serve to decode sign language gestures for intracranial brain–computer interfacing using surface grids.

  1. Effectiveness of pelvic lead blanket to reduce the doses to eye lens and hands of interventional cardiologists and assistant nurses.

    PubMed

    Grabowicz, W; Domienik-Andrzejewska, J; Masiarek, K; Górnik, T; Grycewicz, T; Brodecki, M; Lubiński, A

    2017-09-01

    The aim of the present study is to analyse quantitatively the potential reduction of doses to the eye lens and the hands of an operator and a nurse by the use of a pelvic lead blanket during coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA) procedures. Thermoluminescent dosimeters were used to assess dose levels to the left eye lens and fingers on both hands of both physician and nurses during single procedures performed with or without the lead blanket. The measurements were carried out at one medical centre and include dosimetric data from 100 procedures. Additional measurements including physician's and patient's doses were made on phantoms in the laboratory. In order to determine the reduction potential of the lead blanket, the doses normalized to DAP (Dose-Area Product) corresponding to the same position of dosimeter were compared against each other for both procedure categories (with and without protection). There was no statistically significant decrease observed in physicians' and nurses' eye lens doses, nor in doses normalized to DAP due to the use of the lead pelvic shield in clinic. However, some trend in reducing the eye lens doses by this shield can be observed. Regarding finger doses, the differences are statistically significant but only for physicians. The mean DAP-normalised doses to the eye lens and left and right finger of physicians, in the presence of a ceiling-suspended transparent lead shield, were 2.24e-5 ± 1.41e-5 mSv/μGym(2), 2.31e-4 ± 1.21e-4 mSv/μGym(2), and 2.60e-5 ± 1.57e-5 mSv/μGym(2) for standard procedures performed without the lead blanket, and 1.77e-5 ± 1.17e-5 mSv/μGym(2), 1.70e-4 ± 1.01e-4 mSv/μGym(2), and 1.86e-5 ± 1.13e-5 mSv/μGym(2) for procedures performed with it. A comparison of the results from the laboratory and the clinic shows that they are consistent regarding the eye lens, while for fingers it suggests that the dose reduction properties of the lead shield are related to

  2. Effects of contraction path and velocity on the coordination of hand muscles during a three-digit force production task.

    PubMed

    Jiayuan He; Xinjun Sheng; Dingguo Zhang; Xiangyang Zhu

    2014-01-01

    Though many studies indicated that the behavior of single muscle was different between contraction and relaxation, the effect of contraction history profile on multiple muscles has not been investigated. In this study, we analyzed the influence of contraction history on the coordination patterns of hand muscles during a three-digit force production task. The effects of the contraction and relaxation paths with two contraction velocities (5% and 10% maximum voluntary contraction per second) were investigated. The results showed that the force-independent characteristic of muscle coordination patterns still held regardless of the contraction history profiles. In addition, the effect of contraction path was more significant than that of velocity. The study provides a potential way to overcome the impact of contraction disturbance for improving the robustness of the human-machine interface (HMI) based on electromyographic (EMG) pattern recognition.

  3. The Effects of Hunger on Hand-Mouth Coordination in Newborn Infants.

    ERIC Educational Resources Information Center

    Lew, Adina R.; Butterworth, George

    1995-01-01

    Examined the effects of hunger on the hand-mouth (HM) behavior of a group of newborn infants. Found that significantly more mouth opening before contacts to the mouth than those to the face occurred before but not after feeding, suggesting some link between HM behavior and hunger state. (MDM)

  4. Stewardship of the Evolving Scholarly Record: From the Invisible Hand to Conscious Coordination

    ERIC Educational Resources Information Center

    Lavoie, Brian; Malpas, Constance

    2015-01-01

    The long-term future of the scholarly record in its fullest expression cannot be effectively secured with stewardship strategies designed for print materials. The features of the evolving scholarly record suggest that traditional stewardship strategies, built on an "invisible hand" approach that relies on the uncoordinated,…

  5. The Effects of Hunger on Hand-Mouth Coordination in Newborn Infants.

    ERIC Educational Resources Information Center

    Lew, Adina R.; Butterworth, George

    1995-01-01

    Examined the effects of hunger on the hand-mouth (HM) behavior of a group of newborn infants. Found that significantly more mouth opening before contacts to the mouth than those to the face occurred before but not after feeding, suggesting some link between HM behavior and hunger state. (MDM)

  6. Target Selection by the Frontal Cortex during Coordinated Saccadic and Smooth Pursuit Eye Movements

    ERIC Educational Resources Information Center

    Srihasam, Krishna; Bullock, Daniel; Grossberg, Stephen

    2009-01-01

    Oculomotor tracking of moving objects is an important component of visually based cognition and planning. Such tracking is achieved by a combination of saccades and smooth-pursuit eye movements. In particular, the saccadic and smooth-pursuit systems interact to often choose the same target, and to maximize its visibility through time. How do…

  7. The Coordinated Interplay of Scene, Utterance, and World Knowledge: Evidence from Eye Tracking

    ERIC Educational Resources Information Center

    Knoeferle, Pia; Crocker, Matthew W.

    2006-01-01

    Two studies investigated the interaction between utterance and scene processing by monitoring eye movements in agent-action-patient events, while participants listened to related utterances. The aim of Experiment 1 was to determine if and when depicted events are used for thematic role assignment and structural disambiguation of temporarily…

  8. Coordination of eye and head movements during smooth pursuit in patients with vestibular failure.

    PubMed

    Waterston, J A; Barnes, G R; Grealy, M A; Luxon, L M

    1992-12-01

    During pursuit of smoothly moving targets with combined eye and head movements in normal subjects, accurate gaze control depends on successful interaction of the vestibular and head movement signals with the ocular pursuit mechanisms. To investigate compensation for loss of the vestibulo-ocular reflex during head-free pursuit in labyrinthine-deficient patients, pursuit performance was assessed and compared under head-fixed and head-free conditions in five patients with isolated bilateral loss of vestibular function. Target motion consisted of predictable and unpredictable pseudo-random waveforms containing the sum of three or four sinusoids. Comparison of slow-phase gaze velocity gains under head-free and head-fixed conditions revealed no significant differences during pursuit of any of the three pseudo-random waveforms. The finding of significant compensatory eye movement during active head movements in darkness in labyrinthine-deficient patients, which were comparable in character and gain to the vestibular eye movement elicited in normal subjects, probably explains the similarity of the head-fixed and head-free responses. In two additional patients with cerebellar degeneration and vestibular failure, no compensatory eye movement response was observed, implying that the cerebellum is necessary for the generation of such responses in labyrinthine-deficient patients.

  9. Target Selection by the Frontal Cortex during Coordinated Saccadic and Smooth Pursuit Eye Movements

    ERIC Educational Resources Information Center

    Srihasam, Krishna; Bullock, Daniel; Grossberg, Stephen

    2009-01-01

    Oculomotor tracking of moving objects is an important component of visually based cognition and planning. Such tracking is achieved by a combination of saccades and smooth-pursuit eye movements. In particular, the saccadic and smooth-pursuit systems interact to often choose the same target, and to maximize its visibility through time. How do…

  10. Attenuation of auditory evoked potentials for hand and eye-initiated sounds.

    PubMed

    Mifsud, Nathan G; Beesley, Tom; Watson, Tamara L; Whitford, Thomas J

    2016-10-01

    Reduction of auditory event-related potentials (ERPs) to self-initiated sounds has been considered evidence for a predictive model in which copies of motor commands suppress sensory representations of incoming stimuli. However, in studies which involve arbitrary auditory stimuli evoked by sensory-unspecific motor actions, learned associations may underlie ERP differences. Here, in a new paradigm, eye motor output generated auditory sensory input, a naïve action-sensation contingency. We measured the electroencephalogram (EEG) of 40 participants exposed to pure tones, which they produced with either a button-press or volitional saccade. We found that button-press-initiated stimuli evoked reduced amplitude compared to externally initiated stimuli for both the N1 and P2 ERP components, whereas saccade-initiated stimuli evoked intermediate attenuation at N1 and no reduction at P2. These results indicate that the motor-to-sensory mapping involved in speech production may be partly generalized to other contingencies, and that learned associations also contribute to the N1 attenuation effect.

  11. Can Discrete Joint Action Be Synergistic? Studying the Stabilization of Interpersonal Hand Coordination

    PubMed Central

    Romero, Veronica; Kallen, Rachel; Riley, Michael A.; Richardson, Michael J.

    2016-01-01

    The human perceptual-motor system is tightly coupled to the physical and informational dynamics of a task environment. These dynamics operate to constrain the high-dimensional order of the human movement system into low-dimensional, task-specific synergies—functional groupings of structural elements that are temporarily constrained to act as a single coordinated unit. The aim of the current study was to determine whether synergistic processes operate when coacting individuals coordinate to perform a discrete joint-action task. Pairs of participants sat next to each other and each used 1 arm to complete a pointer-to-target task. Using the uncontrolled manifold (UCM) analysis for the first time in a discrete joint action, the structure of joint-angle variance was examined to determine whether there was synergistic organization of the degrees of freedom employed at the interpersonal or intrapersonal levels. The results revealed that the motor actions performed by coactors were synergistically organized at both the interpersonal and intrapersonal levels. More importantly, however, the interpersonal synergy was found to be significantly stronger than the intrapersonal synergies. Accordingly, the results provide clear evidence that coacting individuals can become temporarily organized to form single synergistic 2-person systems during performance of a discrete joint action. PMID:26052696

  12. Acquisition of Predictable Vertical Visual Targets: Eye-Head Coordination and the Triggering Effect.

    PubMed

    Kolev, Ognyan I; Reschke, Millard F

    2016-01-01

    The study was designed to investigate target acquisition in the vertical plane with emphasis on establishing strategy differences associated with acquisition triggering methods. Eight subjects were tested. Measurements consisted of target acquisition time, eye-head latency differences, velocity of gaze, eyes and head, and head amplitude. Using 3-way repeated measures analyses of variance the results show that the strategy for acquisition of predictable visual targets in vertical plane with the head unrestrained significantly depended on (a) the direction of the gaze motion with respect to the gravity vector (i.e., there is significant up-down asymmetry), (b) the angular distance of the target, and (c) the method of triggering the command to acquire the target-external versus internal. The data also show that when vertical acquisition is compared with triggering methods in the horizontal plane there is a difference in overall strategy for the acquisition of targets with the same spatial distances from straight ahead gaze when both the eyes and head are used. Among the factors contributing to the difference in strategy for vertical target acquisition are the gravitational vector, the relationship of target displacement and vestibular activitation, biomechanical and neural control asymmetries, and the difference in the vertical field of view.

  13. Effects of Repetitive Transcranial Magnetic Stimulation in Performing Eye-Hand Integration Tasks: Four Preliminary Studies with Children Showing Low-Functioning Autism

    ERIC Educational Resources Information Center

    Panerai, Simonetta; Tasca, Domenica; Lanuzza, Bartolo; Trubia, Grazia; Ferri, Raffaele; Musso, Sabrina; Alagona, Giovanna; Di Guardo, Giuseppe; Barone, Concetta; Gaglione, Maria P.; Elia, Maurizio

    2014-01-01

    This report, based on four studies with children with low-functioning autism, aimed at evaluating the effects of repetitive transcranial magnetic stimulation delivered on the left and right premotor cortices on eye-hand integration tasks; defining the long-lasting effects of high-frequency repetitive transcranial magnetic stimulation; and…

  14. Effects of repetitive transcranial magnetic stimulation in performing eye-hand integration tasks: four preliminary studies with children showing low-functioning autism.

    PubMed

    Panerai, Simonetta; Tasca, Domenica; Lanuzza, Bartolo; Trubia, Grazia; Ferri, Raffaele; Musso, Sabrina; Alagona, Giovanna; Di Guardo, Giuseppe; Barone, Concetta; Gaglione, Maria P; Elia, Maurizio

    2014-08-01

    This report, based on four studies with children with low-functioning autism, aimed at evaluating the effects of repetitive transcranial magnetic stimulation delivered on the left and right premotor cortices on eye-hand integration tasks; defining the long-lasting effects of high-frequency repetitive transcranial magnetic stimulation; and investigating the real efficacy of high-frequency repetitive transcranial magnetic stimulation by comparing three kinds of treatments (high-frequency repetitive transcranial magnetic stimulation, a traditional eye-hand integration training, and both treatments combined). Results showed a significant increase in eye-hand performances only when high-frequency repetitive transcranial magnetic stimulation was delivered on the left premotor cortex; a persistent improvement up to 1 h after the end of the stimulation; better outcomes in the treatment combining high-frequency repetitive transcranial magnetic stimulation and eye-hand integration training. Based on these preliminary findings, further evaluations on the usefulness of high-frequency repetitive transcranial magnetic stimulation in rehabilitation of children with autism are strongly recommended.

  15. Effects of Repetitive Transcranial Magnetic Stimulation in Performing Eye-Hand Integration Tasks: Four Preliminary Studies with Children Showing Low-Functioning Autism

    ERIC Educational Resources Information Center

    Panerai, Simonetta; Tasca, Domenica; Lanuzza, Bartolo; Trubia, Grazia; Ferri, Raffaele; Musso, Sabrina; Alagona, Giovanna; Di Guardo, Giuseppe; Barone, Concetta; Gaglione, Maria P.; Elia, Maurizio

    2014-01-01

    This report, based on four studies with children with low-functioning autism, aimed at evaluating the effects of repetitive transcranial magnetic stimulation delivered on the left and right premotor cortices on eye-hand integration tasks; defining the long-lasting effects of high-frequency repetitive transcranial magnetic stimulation; and…

  16. Hand preferences for unimanual and bimanual coordinated actions in olive baboons (Papio anubis): Consistency over time and across populations.

    PubMed

    Molesti, Sandra; Vauclair, Jacques; Meguerditchian, Adrien

    2016-11-01

    The reliability of handedness data in nonhuman primates and variations of sample size across studies are critical issues for exploring their potential continuity with humans concerning hemispheric specialization. In this study, we investigated the consistency of handedness for unimanual and bimanual tasks in olive baboons (Papio anubis). For both tasks, we found a consistency of hand preferences over time among subjects retested 5 years later and a consistency of population-level handedness between 2 independent populations. Altogether, when combining the 2 samples, bimanual (N = 260) but not unimanual task (N = 220) elicited right-handedness predominance. These findings demonstrate the reliability and robustness of predominance of right-handedness in olive baboons for bimanual coordinated behaviors. (PsycINFO Database Record

  17. Dual Logic and Cerebral Coordinates for Reciprocal Interaction in Eye Contact

    PubMed Central

    Lee, Ray F.

    2015-01-01

    In order to scientifically study the human brain’s response to face-to-face social interaction, the scientific method itself needs to be reconsidered so that both quantitative observation and symbolic reasoning can be adapted to the situation where the observer is also observed. In light of the recent development of dyadic fMRI which can directly observe dyadic brain interacting in one MRI scanner, this paper aims to establish a new form of logic, dual logic, which provides a theoretical platform for deductive reasoning in a complementary dual system with emergence mechanism. Applying the dual logic in the dfMRI experimental design and data analysis, the exogenous and endogenous dual systems in the BOLD responses can be identified; the non-reciprocal responses in the dual system can be suppressed; a cerebral coordinate for reciprocal interaction can be generated. Elucidated by dual logic deductions, the cerebral coordinate for reciprocal interaction suggests: the exogenous and endogenous systems consist of the empathy network and the mentalization network respectively; the default-mode network emerges from the resting state to activation in the endogenous system during reciprocal interaction; the cingulate plays an essential role in the emergence from the exogenous system to the endogenous system. Overall, the dual logic deductions are supported by the dfMRI experimental results and are consistent with current literature. Both the theoretical framework and experimental method set the stage to formally apply the scientific method in studying complex social interaction. PMID:25885446

  18. Laterality patterns and visual-motor coordination of children.

    PubMed

    Iteya, M; Gabbard, C

    1996-08-01

    This study examined the association between laterality patterns of eye-hand and eye-foot described as congruent or cross-lateral, and visual-motor coordination skill (target throwing and kicking) by 606 4- to 6-yr.-olds. Speculation derived from contemporary reports of hand preference and motor coordination provided the hypothesis that persons exhibiting congruent patterns of eye and limb laterality such as right-eye and hand or right-eye and foot pattern would perform better than peers who exhibited other laterality patterns. To the contrary, this study yielded no significant differences in motor performance between groups with different patterns of preference. In view of past studies and present results, additional inquiry seems warranted before any consensus regarding the association between laterality and motor coordination can be established.

  19. A Study of the Possible Distinction Between "Controlling Eye" and "Dominant Eye" and the Effect of Both, with Hand Dominance, on Reading Achievement.

    ERIC Educational Resources Information Center

    Boos, Robert W.; Hillerich, Robert L.

    This longitudinal study was a replication of two disparate studies, one of dominance and one of control, which had as subjects 277 seventh- and eighth-grade pupils remaining from an original dominance study of over 500. Eye dominance was determined through hole-in-paper and V-scope; eye control at near and far point, through the telebinocular;…

  20. Robot-assisted retinal vein cannulation with force-based puncture detection: Micron vs. the steady-hand eye robot.

    PubMed

    Gonenc, Berk; Tran, Nhat; Gehlbach, Peter; Taylor, Russell H; Iordachita, Iulian

    2016-08-01

    Retinal vein cannulation is a demanding procedure where therapeutic agents are injected into occluded retina veins. The feasibility of this treatment is limited due to challenges in identifying the moment of venous puncture, achieving cannulation and maintaining it throughout the drug delivery period. In this study, we integrate a force-sensing microneedle with two distinct robotic systems: the handheld micromanipulator Micron, and the cooperatively controlled Steady-Hand Eye Robot (SHER). The sensed tool-to-tissue interaction forces are used to detect venous puncture and extend the robots' standard control schemes with a new position holding mode (PHM) that assists the operator hold the needle position fixed and maintain cannulation for a longer time with less trauma on the vasculature. We evaluate the resulting systems comparatively in a dry phantom, stretched vinyl membranes. Results have shown that modulating the admittance control gain of SHER alone is not a very effective solution for preventing the undesired tool motion after puncture. However, after using puncture detection and PHM the deviation from the puncture point is significantly reduced, by 65% with Micron, and by 95% with SHER representing a potential advantage over freehand for both.

  1. Detection, eye–hand coordination and virtual mobility performance in simulated vision for a cortical visual prosthesis device

    PubMed Central

    Srivastava, Nishant R; Troyk, Philip R; Dagnelie, Gislin

    2014-01-01

    In order to assess visual performance using a future cortical prosthesis device, the ability of normally sighted and low vision subjects to adapt to a dotted ‘phosphene’ image was studied. Similar studies have been conduced in the past and adaptation to phosphene maps has been shown but the phosphene maps used have been square or hexagonal in pattern. The phosphene map implemented for this testing is what is expected from a cortical implantation of the arrays of intracortical electrodes, generating multiple phosphenes. The dotted image created depends upon the surgical location of electrodes decided for implantation and the expected cortical response. The subjects under tests were required to perform tasks requiring visual inspection, eye–hand coordination and way finding. The subjects did not have any tactile feedback and the visual information provided was live dotted images captured by a camera on a head-mounted low vision enhancing system and processed through a filter generating images similar to the images we expect the blind persons to perceive. The images were locked to the subject’s gaze by means of video-based pupil tracking. In the detection and visual inspection task, the subject scanned a modified checkerboard and counted the number of square white fields on a square checkerboard, in the eye–hand coordination task, the subject placed black checkers on the white fields of the checkerboard, and in the way-finding task, the subjects maneuvered themselves through a virtual maze using a game controller. The accuracy and the time to complete the task were used as the measured outcome. As per the surgical studies by this research group, it might be possible to implant up to 650 electrodes; hence, 650 dots were used to create images and performance studied under 0% dropout (650 dots), 25% dropout (488 dots) and 50% dropout (325 dots) conditions. It was observed that all the subjects under test were able to learn the given tasks and showed improvement

  2. Oculo-manual tracking of visual targets: control learning, coordination control and coordination model.

    PubMed

    Gauthier, G M; Vercher, J L; Mussa Ivaldi, F; Marchetti, E

    1988-01-01

    The processes which develop to coordinate eye and hand movements in response to motion of a visual target were studied in young children and adults. We have shown that functional maturation of the coordination control between eye and hand takes place as a result of training. We observed, in the trained child and in the adult, that when the hand is used either as a target or to track a visual target, the dynamic characteristics of the smooth pursuit system are markedly improved: the eye to target delay is decreased from 150 ms in eye alone tracking to 30 ms, and smooth pursuit maximum velocity is increased by 100%. Coordination signals between arm and eye motor systems may be responsible for smooth pursuit eye movements which occur during self-tracking of hand or finger in darkness. These signals may also account for the higher velocity smooth pursuit eye movements and the shortened tracking delay when the hand is used as a target, as well as for the synkinetic eye-arm motions observed at the early stage of oculo-manual tracking training in children. We propose a model to describe the interaction which develops between two systems involved in the execution of a common sensorimotor task. The model applies to the visuo-oculo-manual tracking system, but it may be generalized to other coordinated systems. According to our definition, coordination control results from the reciprocal transfer of sensory and motor information between two or more systems involved in the execution of single, goal-directed or conjugate actions. This control, originating in one or more highly specialized structures of the central nervous system, combines with the control processes normally operating in each system. Our model relies on two essential notions which describe the dynamic and static aspects of coordination control: timing and mutual coupling.

  3. Manual tracking enhances smooth pursuit eye movements.

    PubMed

    Niehorster, Diederick C; Siu, Wilfred W F; Li, Li

    2015-01-01

    Previous studies have reported that concurrent manual tracking enhances smooth pursuit eye movements only when tracking a self-driven or a predictable moving target. Here, we used a control-theoretic approach to examine whether concurrent manual tracking enhances smooth pursuit of an unpredictable moving target. In the eye-hand tracking condition, participants used their eyes to track a Gaussian target that moved randomly along a horizontal axis. In the meantime, they used their dominant hand to move a mouse to control the horizontal movement of a Gaussian cursor to vertically align it with the target. In the eye-alone tracking condition, the target and cursor positions recorded in the eye-hand tracking condition were replayed, and participants only performed eye tracking of the target. Catch-up saccades were identified and removed from the recorded eye movements, allowing for a frequency-response analysis of the smooth pursuit response to unpredictable target motion. We found that the overall smooth pursuit gain was higher and the number of catch-up saccades made was less when eye tracking was accompanied by manual tracking than when not. We conclude that concurrent manual tracking enhances smooth pursuit. This enhancement is a fundamental property of eye-hand coordination that occurs regardless of the predictability of the target motion.

  4. Manual tracking enhances smooth pursuit eye movements

    PubMed Central

    Niehorster, Diederick C.; Siu, Wilfred W. F.; Li, Li

    2015-01-01

    Previous studies have reported that concurrent manual tracking enhances smooth pursuit eye movements only when tracking a self-driven or a predictable moving target. Here, we used a control-theoretic approach to examine whether concurrent manual tracking enhances smooth pursuit of an unpredictable moving target. In the eye-hand tracking condition, participants used their eyes to track a Gaussian target that moved randomly along a horizontal axis. In the meantime, they used their dominant hand to move a mouse to control the horizontal movement of a Gaussian cursor to vertically align it with the target. In the eye-alone tracking condition, the target and cursor positions recorded in the eye-hand tracking condition were replayed, and participants only performed eye tracking of the target. Catch-up saccades were identified and removed from the recorded eye movements, allowing for a frequency-response analysis of the smooth pursuit response to unpredictable target motion. We found that the overall smooth pursuit gain was higher and the number of catch-up saccades made was less when eye tracking was accompanied by manual tracking than when not. We conclude that concurrent manual tracking enhances smooth pursuit. This enhancement is a fundamental property of eye-hand coordination that occurs regardless of the predictability of the target motion. PMID:26605840

  5. Laterality in persons with intellectual disability II. Hand, foot, ear, and eye laterality in persons with Trisomy 21 and Williams-Beuren syndrome.

    PubMed

    Gérard-Desplanches, Aude; Deruelle, Christine; Stefanini, Silvia; Ayoun, Catherine; Volterra, Virginia; Vicari, Stefano; Fisch, Gene; Carlier, Michèle

    2006-09-01

    Laterality (hand, foot, ear, and eye) was assessed in participants with Trisomy 21 (62) and Williams-Beuren syndrome (WBS) (39). Handedness was also assessed in a card reaching task. The comparison group included 184 typically developing persons. Two independent age sub-groups were formed: 7 to 10 years old and 11 to 34 years old. We confirmed previous data: individuals with T21 were more frequently left- or mixed-handed than typically developing persons; individuals with WBS had intermediate scores. The two groups with genetic disorders had less right foot preference. Manual and foot inconsistencies characterized both groups with genetic disorders. Cross hand-foot preference was lower in the typically developing group. Differences in IQ levels did not correlate with differences in laterality scores. Overall laterality profiles were not the same in the two groups with genetic disorders: the greatest differences were observed between typically developing persons and persons with Trisomy 21.

  6. Hemispheric asymmetries in goal-directed hand movements are independent of hand preference.

    PubMed

    Lavrysen, Ann; Heremans, Elke; Peeters, Ron; Wenderoth, Nici; Feys, Peter; Swinnen, Stephan P; Helsen, Werner F

    2012-09-01

    Asymmetries in the kinematics and neural substrates of voluntary right and left eye-hand coordinated movements have been accredited to differential hemispheric specialization. An alternative explanation for between-hand movement differences could result from hand preference related effects. To test both assumptions, an experiment was conducted with left- and right-handers performing goal-directed movements with either hand paced by a metronome. Spatiotemporal accuracy was comparable between hands, whereas hand peak velocity was reached earlier when moving with the left compared to the right hand. The underlying brain activation patterns showed that both left- and right-handers activated more areas involved in visuomotor attention and saccadic control when using their left compared to the right hand. Altogether, these results confirm a unique perceptuomotor processing specialization of the left brain/right hand system that is independent of hand preference. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Eye Injuries (For Parents)

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old Eye Injuries KidsHealth > For Parents > Eye Injuries Print A ... sand, dirt, and other foreign bodies on the eye surface) Wash your hands thoroughly before touching the ...

  8. Let the left hand know what the right is doing: a vision for care coordination and electronic health records.

    PubMed

    Rudin, Robert S; Bates, David W

    2014-01-01

    Despite the potential for electronic health records to help providers coordinate care, the current marketplace has failed to provide adequate solutions. Using a simple framework, we describe a vision of information technology capabilities that could substantially improve four care coordination activities: identifying collaborators, contacting collaborators, collaborating, and monitoring. Collaborators can include any individual clinician, caregiver, or provider organization involved in care for a given patient. This vision can be used to guide the development of care coordination tools and help policymakers track and promote their adoption.

  9. Investigation on Inter-Limb Coordination and Motion Stability, Intensity and Complexity of Trunk and Limbs during Hands-Knees Crawling in Human Adults.

    PubMed

    Ma, Shenglan; Chen, Xiang; Cao, Shuai; Yu, Yi; Zhang, Xu

    2017-03-28

    This study aimed to investigate the inter-limb coordination pattern and the stability, intensity, and complexity of the trunk and limbs motions in human crawling under different speeds. Thirty healthy human adults finished hands-knees crawling trials on a treadmill at six different speeds (from 1 km/h to 2.5 km/h). A home-made multi-channel acquisition system consisting of five 3-axis accelerometers (ACC) and four force sensors was used for the data collection. Ipsilateral phase lag was used to represent inter-limb coordination pattern during crawling and power, harmonic ratio, and sample entropy of acceleration signals were adopted to depict the motion intensity, stability, and complexity of trunk and limbs respectively. Our results revealed some relationships between inter-limb coordination patterns and the stability and complexity of trunk movement. Trot-like crawling pattern was found to be the most stable and regular one at low speed in the view of trunk movement, and no-limb-pairing pattern showed the lowest stability and the greatest complexity at high speed. These relationships could be used to explain why subjects tended to avoid no-limb-pairing pattern when speed was over 2 km/h no matter which coordination type they used at low speeds. This also provided the evidence that the central nervous system (CNS) chose a stable inter-limb coordination pattern to keep the body safe and avoid tumbling. Although considerable progress has been made in the study of four-limb locomotion, much less is known about the reasons for the variety of inter-limb coordination. The research results of the exploration on the inter-limb coordination pattern choice during crawling from the standpoint of the motion stability, intensity, and complexity of trunk and limbs sheds light on the underlying motor control strategy of the human CNS and has important significance in the fields of clinical diagnosis, rehabilitation engineering, and kinematics research.

  10. Movement constraints on interpersonal coordination and communication.

    PubMed

    Tolston, Michael T; Shockley, Kevin; Riley, Michael A; Richardson, Michael J

    2014-10-01

    The present study investigated how constraining movement affects interpersonal coordination and joint cognitive performance. Pairs of participants worked cooperatively to solve picture-puzzle tasks in which they conversed to identify differences between pictures in 3 degree-of-constraint conditions: both participants were free to move their hands (free-free; FF); both participants' hands were restrained (restrained-restrained; RR); and the hands of 1 participant were free while the hands of the other participant were restrained (free-restrained; FR). Eye tracking data were collected, and movement was measured at the waist, hand, and head. Data were analyzed using Cross-Recurrence Quantification Analysis (CRQ). Postural sway coordination, gaze coordination, and task performance were predicted to be highest in FF, followed by RR, and then by FR. Results showed the asymmetric FR condition generally exhibited lesser degrees of coordination than the symmetric Conditions FF and RR, and that the patterning of coordination in the symmetric conditions varied across the measured body segments. These results demonstrate that movement restraints affect not only interpersonal postural coordination, but also joint attention. Additionally, significant positive relationships were found between task performance and total amount of anterior-posterior movement measured at the head, hand and waist; number of utterances; and number of differences pairs found in the puzzles. These findings indicate a relationship between movement and task performance consistent with the hypotheses that both interpersonal coordination and cognitive performance are sensitive to local action constraints.

  11. Task-Irrelevant Expectation Violations in Sequential Manual Actions: Evidence for a “Check-after-Surprise” Mode of Visual Attention and Eye-Hand Decoupling

    PubMed Central

    Foerster, Rebecca M.

    2016-01-01

    When performing sequential manual actions (e.g., cooking), visual information is prioritized according to the task determining where and when to attend, look, and act. In well-practiced sequential actions, long-term memory (LTM)-based expectations specify which action targets might be found where and when. We have previously demonstrated (Foerster and Schneider, 2015b) that violations of such expectations that are task-relevant (e.g., target location change) cause a regression from a memory-based mode of attentional selection to visual search. How might task-irrelevant expectation violations in such well-practiced sequential manual actions modify attentional selection? This question was investigated by a computerized version of the number-connection test. Participants clicked on nine spatially distributed numbered target circles in ascending order while eye movements were recorded as proxy for covert attention. Target’s visual features and locations stayed constant for 65 prechange-trials, allowing practicing the manual action sequence. Consecutively, a task-irrelevant expectation violation occurred and stayed for 20 change-trials. Specifically, action target number 4 appeared in a different font. In 15 reversion-trials, number 4 returned to the original font. During the first task-irrelevant change trial, manual clicking was slower and eye scanpaths were larger and contained more fixations. The additional fixations were mainly checking fixations on the changed target while acting on later targets. Whereas the eyes repeatedly revisited the task-irrelevant change, cursor-paths remained completely unaffected. Effects lasted for 2–3 change trials and did not reappear during reversion. In conclusion, an unexpected task-irrelevant change on a task-defining feature of a well-practiced manual sequence leads to eye-hand decoupling and a “check-after-surprise” mode of attentional selection. PMID:27933016

  12. Task-Irrelevant Expectation Violations in Sequential Manual Actions: Evidence for a "Check-after-Surprise" Mode of Visual Attention and Eye-Hand Decoupling.

    PubMed

    Foerster, Rebecca M

    2016-01-01

    When performing sequential manual actions (e.g., cooking), visual information is prioritized according to the task determining where and when to attend, look, and act. In well-practiced sequential actions, long-term memory (LTM)-based expectations specify which action targets might be found where and when. We have previously demonstrated (Foerster and Schneider, 2015b) that violations of such expectations that are task-relevant (e.g., target location change) cause a regression from a memory-based mode of attentional selection to visual search. How might task-irrelevant expectation violations in such well-practiced sequential manual actions modify attentional selection? This question was investigated by a computerized version of the number-connection test. Participants clicked on nine spatially distributed numbered target circles in ascending order while eye movements were recorded as proxy for covert attention. Target's visual features and locations stayed constant for 65 prechange-trials, allowing practicing the manual action sequence. Consecutively, a task-irrelevant expectation violation occurred and stayed for 20 change-trials. Specifically, action target number 4 appeared in a different font. In 15 reversion-trials, number 4 returned to the original font. During the first task-irrelevant change trial, manual clicking was slower and eye scanpaths were larger and contained more fixations. The additional fixations were mainly checking fixations on the changed target while acting on later targets. Whereas the eyes repeatedly revisited the task-irrelevant change, cursor-paths remained completely unaffected. Effects lasted for 2-3 change trials and did not reappear during reversion. In conclusion, an unexpected task-irrelevant change on a task-defining feature of a well-practiced manual sequence leads to eye-hand decoupling and a "check-after-surprise" mode of attentional selection.

  13. The Use of Bouts and Frequencies in the Evaluation of Hand Preferences for a Coordinated Bimanual Task in Chimpanzees (Pan troglodytes): An Empirical Study Comparing Two Different Indices of Laterality

    PubMed Central

    Hopkins, William D.; Wesley, Micheal J.; Hostetter, Autumn; Fernandez-Carriba, Samuel; Pilcher, Dawn; Poss, Sarah

    2007-01-01

    Hand preferences for a coordinated bimanual task were assessed in 109 chimpanzees (Pan troglodytes). Hand preference was evaluated for 4 test sessions using bouts and frequencies of hand use to compare the sensitivity of each level of analysis in evaluating individual variation in handedness. Overall, significant population-level right-handedness was found using several different measures of hand use. Handedness indices based on bouts and frequencies were highly and significantly correlated. Moreover, hand preferences were consistent across tests despite efforts to situationally bias preference during each test. Taken together, these data do not support the view that bouts are a better level of analysis for evaluating hand preference. The results further suggest that hand preferences for coordinated bimanual actions are not influenced by situational factors and may reflect an inherent specialization of the left hemisphere for motor skill. PMID:11594498

  14. Coordination of intrinsic and extrinsic hand muscle activity as a function of wrist joint angle during two-digit grasping.

    PubMed

    Johnston, Jamie A; Bobich, Lisa R; Santello, Marco

    2010-04-26

    Fingertip forces result from the activation of muscles that cross the wrist and muscles whose origins and insertions reside within the hand (extrinsic and intrinsic hand muscles, respectively). Thus, tasks that involve changes in wrist angle affect the moment arm and length, hence the force-producing capabilities, of extrinsic muscles only. If a grasping task requires the exertion of constant fingertip forces, the Central Nervous System (CNS) may respond to changes in wrist angle by modulating the neural drive to extrinsic or intrinsic muscles only or by co-activating both sets of muscles. To distinguish between these scenarios, we recorded electromyographic (EMG) activity of intrinsic and extrinsic muscles of the thumb and index finger as a function of wrist angle during a two-digit object hold task. We hypothesized that changes in wrist angle would elicit EMG amplitude modulation of the extrinsic and intrinsic hand muscles. In one experimental condition we asked subjects to exert the same digit forces at each wrist angle, whereas in a second condition subjects could choose digit forces for holding the object. EMG activity was significantly modulated in both extrinsic and intrinsic muscles as a function of wrist angle (both p<0.05) but only for the constant force condition. Furthermore, EMG modulation resulted from uniform scaling of EMG amplitude across all muscles. We conclude that the CNS controlled both extrinsic and intrinsic muscles as a muscle synergy. These findings are discussed within the theoretical frameworks of synergies and common neural input across motor nuclei of hand muscles. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

  15. Coordination of intrinsic and extrinsic hand muscle activity as a function of wrist joint angle during two-digit grasping

    PubMed Central

    Johnston, Jamie A.; Bobich, Lisa R.; Santello, Marco

    2010-01-01

    Fingertip forces result from activation of muscles that cross the wrist and muscles whose origins and insertions reside within the hand (extrinsic and intrinsic hand muscles, respectively). Thus, tasks that involve changes in wrist angle affect the moment arm and length, hence the force-producing capabilities, of extrinsic muscles only. If a grasping task requires the exertion of constant fingertip forces, the Central Nervous System (CNS) may respond to changes in wrist angle by modulating the neural drive to extrinsic or intrinsic muscles only or by co-activating both sets of muscles. To distinguish between these scenarios, we recorded electromyographic (EMG) activity of intrinsic and extrinsic muscles of the thumb and index finger as a function of wrist angle during a two-digit object hold task. We hypothesized that changes in wrist angle would elicit EMG amplitude modulation of the extrinsic and intrinsic hand muscles. In one experimental condition we asked subjects to exert the same digit forces at each wrist angle, whereas in a second condition subjects could choose digit forces for holding the object. EMG activity was significantly modulated in both extrinsic and intrinsic muscles as a function of wrist angle (both p < 0.05) but only for the constant force condition. Furthermore, EMG modulation resulted from uniform scaling of EMG amplitude across all muscles. We conclude that the CNS controlled both extrinsic and intrinsic muscles as a muscle synergy. These findings are discussed within the theoretical frameworks of synergies and common neural input across motor nuclei of hand muscles. PMID:20227463

  16. Training the Eyes for Competition: Fighting Eyes.

    ERIC Educational Resources Information Center

    Williams, Darrell; Bradford, Vincent

    1989-01-01

    Fencers should be taught to discipline their eyes to focus on the opponent's hand. The rationale for this strategy as well as drills to develop "hand watching" skills are presented in this article. (IAH)

  17. Successes and Difficulties in the Individual Inclusion of Children with Autism Spectrum Disorder (ASD) in the Eyes of Their Coordinators

    ERIC Educational Resources Information Center

    Eldar, Eitan; Talmor, Rachel; Wolf-Zukerman, Tali

    2010-01-01

    This study examined the inclusion of children with Autism Spectrum Disorder (ASD) in regular classes and analysed the factors related to its success and failure. Thirty-seven inclusion coordinators participated in the study and conveyed their view about their own experience. The qualitative methodology used in this study was comprised of regular…

  18. Handedness, eyedness, and crossed hand-eye dominance in male and female patients with migraine with and without aura: a pilot study.

    PubMed

    Aygül, Recep; Dane, Senol; Ulvi, Hizir

    2005-06-01

    The possible relationships of migraine to left-handedness and left-eyedness, as well as sex and aura-related differences, were examined. 146 migraine patients (M age=32.1 yr., SD=9.5) and 141 controls (M age=30.0 yr., SD=9.3) participated. Hand preference was assessed by the modified version of the Edinburgh Handedness Inventory. Ocular dominance was measured by means of the near-far alignment test. Migraine diagnoses were made on the basis of criteria provided from the International Headache Society. In the overall sample and in women, left-handedness and left-eyedness were not significantly correlated with migraine. In men, the incidence of left-handedness and left-eyedness were significantly higher in patients than in controls. The presence of aura in patients with migraine was significantly associated with the incidence of left-eyedness and crossed hand-eye dominance, but not handedness, for the total sample and women. These results suggest that there may be a tendency towards anomalous dominance, especially left-eyedness, in migraine patients particularly those with aura.

  19. Hand preferences for coordinated bimanual actions in 777 great apes: implications for the evolution of handedness in hominins.

    PubMed

    Hopkins, William D; Phillips, Kimberley A; Bania, Amanda; Calcutt, Sarah E; Gardner, Molly; Russell, Jamie; Schaeffer, Jennifer; Lonsdorf, Elizabeth V; Ross, Stephen R; Schapiro, Steven J

    2011-05-01

    Whether or not nonhuman primates exhibit population-level handedness remains a topic of considerable scientific debate. Here, we examined handedness for coordinated bimanual actions in a sample of 777 great apes including chimpanzees, bonobos, gorillas, and orangutans. We found population-level right-handedness in chimpanzees, bonobos and gorillas, but left-handedness in orangutans. Directional biases in handedness were consistent across independent samples of apes within each genus. We suggest that, contrary to previous claims, population-level handedness is evident in great apes but differs among species as a result of ecological adaptations associated with posture and locomotion. We further suggest that historical views of nonhuman primate handedness have been too anthropocentric, and we advocate for a larger evolutionary framework for the consideration of handedness and other aspects of hemispheric specialization among primates. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Hand Preferences for Coordinated Bimanual Actions in 777 Great Apes: Implications for the Evolution of Handedness in Hominins

    PubMed Central

    Hopkins, William D.; Phillips, Kimberley A.; Bania, Amanda; Calcutt, Sarah E.; Gardner, Molly; Russell, Jamie; Schaeffer, Jennifer; Lonsdorf, Elizabeth V.; Ross, Stephen R.; Schapiro, Steven J.

    2011-01-01

    Whether or not nonhuman primates exhibit population-level handedness remains a topic of considerable scientific debate. Here, we examined handedness for coordinated bimanual actions in a sample of 777 great apes including chimpanzees, bonobos, gorillas, and orangutans. We found population-level right-handedness in chimpanzees, bonobos and gorillas, but left-handedness in orangutans. Directional biases in handedness were consistent across independent samples of apes within each genus. We suggest that, contrary to previous claims, population-level handedness is evident in great apes but differs among species as a result of ecological adaptations associated with posture and locomotion. We further suggest that historical views of nonhuman primate handedness have been too anthropocentric, and we advocate for a larger evolutionary framework for the consideration of handedness and other aspects of hemispheric specialization among primates. PMID:21334723

  1. Limitations of gaze transfer: without visual context, eye movements do not to help to coordinate joint action, whereas mouse movements do.

    PubMed

    Müller, Romy; Helmert, Jens R; Pannasch, Sebastian

    2014-10-01

    Remote cooperation can be improved by transferring the gaze of one participant to the other. However, based on a partner's gaze, an interpretation of his communicative intention can be difficult. Thus, gaze transfer has been inferior to mouse transfer in remote spatial referencing tasks where locations had to be pointed out explicitly. Given that eye movements serve as an indicator of visual attention, it remains to be investigated whether gaze and mouse transfer differentially affect the coordination of joint action when the situation demands an understanding of the partner's search strategies. In the present study, a gaze or mouse cursor was transferred from a searcher to an assistant in a hierarchical decision task. The assistant could use this cursor to guide his movement of a window which continuously opened up the display parts the searcher needed to find the right solution. In this context, we investigated how the ease of using gaze transfer depended on whether a link could be established between the partner's eye movements and the objects he was looking at. Therefore, in addition to the searcher's cursor, the assistant either saw the positions of these objects or only a grey background. When the objects were visible, performance and the number of spoken words were similar for gaze and mouse transfer. However, without them, gaze transfer resulted in longer solution times and more verbal effort as participants relied more strongly on speech to coordinate the window movement. Moreover, an analysis of the spatio-temporal coupling of the transmitted cursor and the window indicated that when no visual object information was available, assistants confidently followed the searcher's mouse but not his gaze cursor. Once again, the results highlight the importance of carefully considering task characteristics when applying gaze transfer in remote cooperation. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Electromyographic Activity of Hand Muscles in a Motor Coordination Game: Effect of Incentive Scheme and Its Relation with Social Capital

    PubMed Central

    Censolo, Roberto; Craighero, Laila; Ponti, Giovanni; Rizzo, Leonzio; Canto, Rosario; Fadiga, Luciano

    2011-01-01

    Background A vast body of social and cognitive psychology studies in humans reports evidence that external rewards, typically monetary ones, undermine intrinsic motivation. These findings challenge the standard selfish-rationality assumption at the core of economic reasoning. In the present work we aimed at investigating whether the different modulation of a given monetary reward automatically and unconsciously affects effort and performance of participants involved in a game devoid of visual and verbal interaction and without any perspective-taking activity. Methodology/Principal Findings Twelve pairs of participants were submitted to a simple motor coordination game while recording the electromyographic activity of First Dorsal Interosseus (FDI), the muscle mainly involved in the task. EMG data show a clear effect of alternative rewards strategies on subjects' motor behavior. Moreover, participants' stock of relevant past social experiences, measured by a specifically designed questionnaire, was significantly correlated with EMG activity, showing that only low social capital subjects responded to monetary incentives consistently with a standard rationality prediction. Conclusions/Significance Our findings show that the effect of extrinsic motivations on performance may arise outside social contexts involving complex cognitive processes due to conscious perspective-taking activity. More importantly, the peculiar performance of low social capital individuals, in agreement with standard economic reasoning, adds to the knowledge of the circumstances that makes the crowding out/in of intrinsic motivation likely to occur. This may help in improving the prediction and accuracy of economic models and reconcile this puzzling effect of external incentives with economic theory. PMID:21464986

  3. Electromyographic activity of hand muscles in a motor coordination game: effect of incentive scheme and its relation with social capital.

    PubMed

    Censolo, Roberto; Craighero, Laila; Ponti, Giovanni; Rizzo, Leonzio; Canto, Rosario; Fadiga, Luciano

    2011-03-25

    A vast body of social and cognitive psychology studies in humans reports evidence that external rewards, typically monetary ones, undermine intrinsic motivation. These findings challenge the standard selfish-rationality assumption at the core of economic reasoning. In the present work we aimed at investigating whether the different modulation of a given monetary reward automatically and unconsciously affects effort and performance of participants involved in a game devoid of visual and verbal interaction and without any perspective-taking activity. Twelve pairs of participants were submitted to a simple motor coordination game while recording the electromyographic activity of First Dorsal Interosseus (FDI), the muscle mainly involved in the task. EMG data show a clear effect of alternative rewards strategies on subjects' motor behavior. Moreover, participants' stock of relevant past social experiences, measured by a specifically designed questionnaire, was significantly correlated with EMG activity, showing that only low social capital subjects responded to monetary incentives consistently with a standard rationality prediction. Our findings show that the effect of extrinsic motivations on performance may arise outside social contexts involving complex cognitive processes due to conscious perspective-taking activity. More importantly, the peculiar performance of low social capital individuals, in agreement with standard economic reasoning, adds to the knowledge of the circumstances that makes the crowding out/in of intrinsic motivation likely to occur. This may help in improving the prediction and accuracy of economic models and reconcile this puzzling effect of external incentives with economic theory.

  4. On the origins of human handedness and language: a comparative review of hand preferences for bimanual coordinated actions and gestural communication in nonhuman primates.

    PubMed

    Meguerditchian, Adrien; Vauclair, Jacques; Hopkins, William D

    2013-09-01

    Within the evolutionary framework about the origin of human handedness and hemispheric specialization for language, the question of expression of population-level manual biases in nonhuman primates and their potential continuities with humans remains controversial. Nevertheless, there is a growing body of evidence showing consistent population-level handedness particularly for complex manual behaviors in both monkeys and apes. In the present article, within a large comparative approach among primates, we will review our contribution to the field and the handedness literature related to two particular sophisticated manual behaviors regarding their potential and specific implications for the origins of hemispheric specialization in humans: bimanual coordinated actions and gestural communication. Whereas bimanual coordinated actions seem to elicit predominance of left-handedness in arboreal primates and of right-handedness in terrestrial primates, all handedness studies that have investigated gestural communication in several primate species have reported stronger degree of population-level right-handedness compared to noncommunicative actions. Communicative gestures and bimanual actions seem to affect differently manual asymmetries in both human and nonhuman primates and to be related to different lateralized brain substrates. We will discuss (1) how the data of hand preferences for bimanual coordinated actions highlight the role of ecological factors in the evolution of handedness and provide additional support the postural origin theory of handedness proposed by MacNeilage [MacNeilage [2007]. Present status of the postural origins theory. In W. D. Hopkins (Ed.), The evolution of hemispheric specialization in primates (pp. 59-91). London: Elsevier/Academic Press] and (2) the hypothesis that the emergence of gestural communication might have affected lateralization in our ancestor and may constitute the precursors of the hemispheric specialization for language.

  5. Eyes absent 1 (Eya1) is a critical coordinator of epithelial, mesenchymal and vascular morphogenesis in the mammalian lung

    PubMed Central

    El-Hashash, Ahmed HK; Alam, Denise Al; Turcatel, Gianluca; Bellusci, Saverio; Warburton, David

    2011-01-01

    The proper level of proliferation and differentiation along the proximodistal axis is crucial for lung organogenesis. Elucidation of the factors that control these processes will therefore provide important insights into embryonic lung development and regeneration. Eya1 is a transcription factor/protein phosphatase that regulates cell lineage specification and proliferation. Yet its functions during lung development are unknown. In this paper we show that Eya1-/- lungs are severely hypoplastic with reduced epithelial branching and increased mesenchymal cellularity. Eya1 is expressed at the distal epithelial tips of branching tubules as well as in the surrounding distal mesenchyme. Eya1-/- lung epithelial cells show loss of progenitor cell markers with increased expression of differentiation markers and cell cycle exit. In addition, Eya1–/– embryos and newborn mice exhibit severe defects in the smooth muscle component of the bronchi and major pulmonary vessels with decreased Fgf10 expression. These defects lead to rupture of the major vessels and hemorrhage into the lungs after birth. Treatment of Eya1-/- epithelial explants in culture with recombinant Fgf10 stimulates epithelial branching. Since Shh expression and activity are abnormally increased in Eya1-/- lungs, we tested whether genetically lowering Shh activity could rescue the Eya1-/- lung phenotype. Indeed, genetic reduction of Shh partially rescues Eya1-/- lung defects while restoring Fgf10 expression. This study provides the first evidence that Eya1 regulates Shh signaling in embryonic lung, thus ensuring the proper level of proliferation and differentiation along the proximodistal axis of epithelial, mesenchymal and endothelial cells. These findings uncover novel functions for Eya1 as a critical upstream coordinator of Shh-Fgf10 signaling during embryonic lung development. We conclude, therefore, that Eya1 function is critical for proper coordination of lung epithelial, mesenchymal and vascular

  6. Eye-head coordination in the guinea pig II. Responses to self-generated (voluntary) head movements

    PubMed Central

    Shanidze, N.; Kim, A. H.; Loewenstein, S.; Raphael, Y.; King, W. M.

    2010-01-01

    Retinal image stability is essential for vision but may be degraded by head movements. The vestibulo-ocular reflex (VOR) compensates for passive perturbations of head position and is usually assumed to be the major neural mechanism for ocular stability. During our recent investigation of vestibular reflexes in guinea pigs free to move their heads (Shanidze et al 2010), we observed compensatory eye movements that could not have been initiated either by vestibular or neck proprioceptive reflexes because they occurred with zero or negative latency with respect to head movement. These movements always occurred in association with self-generated (active) head or body movements and thus anticipated a voluntary movement. We found the anticipatory responses to differ from those produced by the VOR in two significant ways. First, anticipatory responses are characterized by temporal synchrony with voluntary head movements (latency ~1 msec versus ~7 msec for the VOR). Second, the anticipatory responses have higher gains (0.80 versus 0.46 for the VOR) and thus more effectively stabilize the retinal image during voluntary head movements. We suggest that anticipatory responses act synergistically with the VOR to stabilize retinal images. Furthermore, they are independent of actual vestibular sensation since they occur in guinea pigs with complete peripheral vestibular lesions. Conceptually, anticipatory responses could be produced by a feed-forward neural controller that transforms efferent motor commands for head movement into estimates of the sensory consequences of those movements. PMID:20697698

  7. Dry eye syndrome

    MedlinePlus

    ... of dry eyes include: Dry environment or workplace (wind, air conditioning) Sun exposure Smoking or second-hand ... NOT smoke and avoid second-hand smoke, direct wind, and air conditioning. Use a humidifier, especially in ...

  8. Stopping eyes and hands: evidence for non-independence of stop and go processes and for a separation of central and peripheral inhibition

    PubMed Central

    Gulberti, Alessandro; Arndt, Petra A.; Colonius, Hans

    2014-01-01

    In the stop-signal paradigm, participants perform a primary reaction task, for example a visual or auditory discrimination task, and have to react to a go stimulus as quickly as possible with a specified motor response. In a certain percentage of trials, after presentation of the stimulus (go signal), another stimulus (stop signal) is presented with a variable stop-signal delay. Whenever a stop signal occurs, the participant is asked to inhibit the execution of the response. Here, an extended test of the popular horse race model for this task (Logan and Cowan, 1984) is presented. Responses for eye and hand movements in both single-task and dual-task conditions were collected. Saccadic reaction times revealed some significant violations of the model's basic assumption of independent go and inhibition processes for all six participants. Saccades that escaped an early stop signal were systematically slower and had smaller amplitudes compared to saccades without a stop signal. Moreover, the analysis of concomitant electromyographic responses recorded from the upper arm suggests the existence of two separate inhibitory mechanisms: a slow, selective, central inhibitory mechanism and a faster, highly efficient, peripheral one, which is probably ineffective for saccades. PMID:24600371

  9. Eye Movements of Flatfish for Different Gravity Condition

    NASA Astrophysics Data System (ADS)

    Iwata, Kaori; Takabayashi, Akira; Imada, Hideki; Miyachi, Ei-Ichi

    On Earth, gravity sensation plays a basic role for all of physiological phenomena in every creature. In microgravity, loss of gravity input causes many functional disorders in animals and humans. During adaptation to microgravity, otolith-mediated response such as eye movements would alter. Flatfish provide a natural model for the study of adaptive changes in the vestibuloocular reflex. During metamorphosis, vestibular and oculomotor coordinate of flatfish displaced 90 degrees about the longitudinal body axis. Therefore, it is expected that microgravity induce the sensory mismatch in adult flatfish. In this study, we analyzed the eye movements of normal and otolith removed flatfish for body tilting and the eye movements of normal flatfish during microgravity produced by parabolic aircraft flight. The fish was fixed on the tilting table controlled by computer. The eye movements for body tilting along the different body axis were video-recorded. The vertical and torsional eye rotations were analyzed frame by frame. In normal flatfish, torsional eye movements were larger for head up or head down tilting than leftward or rightward tilting. On the other hand, vertical eye movements were larger for leftward or rightward tilting than head up or head down tilting. After removal of left side utlicular otolith, the vertical eye movement for 180 degrees body tilting disappeared. For the changes of gravity, vertical eye movements were observed. These results suggested that eye movements of flatfish adapted to Earth's gravity condition and sacculus and lagena might play important role for otolith-ocular eye movements.

  10. Evaluation of the Effect of Noise on the Rate of Errors and Speed of Work by the Ergonomic Test of Two-Hand Co-Ordination

    PubMed Central

    Habibi, Ehsanollah; Dehghan, Habibollah; Dehkordy, Sina Eshraghy; Maracy, Mohammad Reza

    2013-01-01

    Background: Among the most important and effective factors affecting the efficiency of the human workforce are accuracy, promptness, and ability. In the context of promoting levels and quality of productivity, the aim of this study was to investigate the effects of exposure to noise on the rate of errors, speed of work, and capability in performing manual activities. Methods: This experimental study was conducted on 96 students (52 female and 44 male) of the Isfahan Medical Science University with the average and standard deviations of age, height, and weight of 22.81 (3.04) years, 171.67 (8.51) cm, and 65.05 (13.13) kg, respectively. Sampling was conducted with a randomized block design. Along with controlling for intervening factors, a combination of sound pressure levels [65 dB (A), 85 dB (A), and 95 dB (A)] and exposure times (0, 20, and 40) were used for evaluation of precision and speed of action of the participants, in the ergonomic test of two-hand coordination. Data was analyzed by SPSS18 software using a descriptive and analytical statistical method by analysis of covariance (ANCOVA) repeated measures. Results: The results of this study showed that increasing sound pressure level from 65 to 95 dB in network ‘A’ increased the speed of work (P < 0.05). Increase in the exposure time (0 to 40 min of exposure) and gender showed no significant differences statistically in speed of work (P > 0.05). Male participants got annoyed from the noise more than females. Also, increase in sound pressure level increased the rate of error (P < 0.05). Conclusions: According to the results of this research, increasing the sound pressure level decreased efficiency and increased the errors and in exposure to sounds less than 85 dB in the beginning, the efficiency decreased initially and then increased in a mild slope. PMID:23930164

  11. Arm-eye coordination test to objectively quantify motor performance and muscles activation in persons after stroke undergoing robot-aided rehabilitation training: a pilot study.

    PubMed

    Song, Rong; Tong, Kai-Yu; Hu, Xiaoling; Li, Le; Sun, Rui

    2013-09-01

    This study designed an arm-eye coordination test to investigate the effectiveness of the robot-aided rehabilitation for persons after stroke. Six chronic poststroke subjects were recruited to attend a 20-session robot-aided rehabilitation training of elbow joint. Before and after the training program, subjects were asked to perform voluntary movements of elbow flection and extension by following sinusoidal trajectories at different velocities with visual feedback on their joint positions. The elbow angle and the electromyographic signal of biceps and triceps as well as clinical scores were evaluated together with the parameters. Performance was objectively quantified by root mean square error (RMSE), root mean square jerk (RMSJ), range of motion (ROM), and co-contraction index (CI). After 20 sessions, RMSE and ROM improved significantly in both the affected and the unaffected side based on two-way ANOVA (P < 0.05). There was significant lower RMSJ in the affected side at higher velocities (P < 0.05). There was significant negative correlation between average RMSE with different tracking velocities and Fugl-Meyer shoulder-elbow score (P < 0.05). There was also significant negative correlation between average RMSE and average ROM (P < 0.05), and moderate nonsignificant negative correlation with RMSJ, and CI. The characterization of velocity-dependent deficiencies, monitoring of training-induced improvement, and the correlation between quantitative parameters and clinical scales could enable the exploration of effects of different types of treatment and design progress-based training method to accelerate the processes of recovery.

  12. The Arrangement of Instruments, the Distance between Instruments, and the Position of Instrument Pointers as Determinants of Performance in an Eye-Hand Coordination Task

    DTIC Science & Technology

    1952-02-01

    and requires frequent change of set« Connell and Grether (2), Warrlck and Orether (15)« tad White (16) have reported differences in the ability to...2. Conaell, Shirley C. and Grether , W. F. Pgvchologlcal fee» tors in saasfc radlat glasig, lpstruaentg* *EAF Air Materiel Cosmand, Dayton...Government Printing Office, 19*7. 9« Grether , W. F. A duel cosmansatorv pursuit apparatus for use ID MSSacigSlSftl XatagSISa» JSAF Air Materiel Conaand

  13. A Study of Early Elementary Teacher Evaluation of Selected Eye-Hand Coordination Skills of Kindergarten Children. Ingham Intermediate Cooperative Research Project, 1967-68: Summary Report.

    ERIC Educational Resources Information Center

    1968

    It was the purpose of this study to investigate and compare the expectations of the school for the child and the expectations based on research findings from the field of child growth and development and to discover the nature of the discrepancy, if any, between these two expectations. Data was gathered for comparing the evaluations of early…

  14. Eye Cancer

    MedlinePlus

    ... Cancer > Eye Cancer > Eye Cancer: Overview Request Permissions Eye Cancer: Overview Approved by the Cancer.Net Editorial ... trained to treat intraocular cancer. Parts of the eye The eye is the organ that collects light ...

  15. Eye Infections

    MedlinePlus

    Your eyes can get infections from bacteria, fungi, or viruses. Eye infections can occur in different parts of the eye and can affect just one eye or both. Two common eye infections are Conjunctivitis - also known as pinkeye. Conjunctivitis is ...

  16. Magnetic eye tracking in mice.

    PubMed

    Payne, Hannah L; Raymond, Jennifer L

    2017-09-05

    Eye movements provide insights about a wide range of brain functions, from sensorimotor integration to cognition; hence, the measurement of eye movements is an important tool in neuroscience research. We describe a method, based on magnetic sensing, for measuring eye movements in head-fixed and freely moving mice. A small magnet was surgically implanted on the eye, and changes in the magnet angle as the eye rotated were detected by a magnetic field sensor. Systematic testing demonstrated high resolution measurements of eye position of <0.1°. Magnetic eye tracking offers several advantages over the well-established eye coil and video-oculography methods. Most notably, it provides the first method for reliable, high-resolution measurement of eye movements in freely moving mice, revealing increased eye movements and altered binocular coordination compared to head-fixed mice. Overall, magnetic eye tracking provides a lightweight, inexpensive, easily implemented, and high-resolution method suitable for a wide range of applications.

  17. An Eye for Learning.

    ERIC Educational Resources Information Center

    Ostwald, Thomas

    1995-01-01

    Presents a hands-on activity as an excellent starting point for investigations related to the eye. Involves making a simple model of the vertebrate eye to illustrate the formation of an upside-down image on the retina by the lens. Links to investigations in numerous science disciplines including astronomy, genetics, biology, earth science, and…

  18. An Eye for Learning.

    ERIC Educational Resources Information Center

    Ostwald, Thomas

    1995-01-01

    Presents a hands-on activity as an excellent starting point for investigations related to the eye. Involves making a simple model of the vertebrate eye to illustrate the formation of an upside-down image on the retina by the lens. Links to investigations in numerous science disciplines including astronomy, genetics, biology, earth science, and…

  19. Hand to hand.

    PubMed

    Bedell, Susanna E; Graboys, Thomas B

    2002-08-01

    Examination of the hands has the potential to transform the encounter between physician and patient. Taking the hands conveys a sense of warmth and connectedness and is a means to communicate the physician's mindfulness. The hands can focus the examination on the individual patient as a complete human being, and not merely a disease or a collection of symptoms. The hands provide readily accessible information that may not be available through other evaluations, and they offer clues to a patient's physical and mental health. Commonplace observations, such as those revealed in the hands, can unravel medical mysteries and provide profound clinical insights.

  20. Handedness for Unimanual Grasping in 564 Great Apes: The Effect on Grip Morphology and a Comparison with Hand Use for a Bimanual Coordinated Task

    PubMed Central

    Meguerditchian, Adrien; Phillips, Kimberley A.; Chapelain, Amandine; Mahovetz, Lindsay M.; Milne, Scott; Stoinski, Tara; Bania, Amanda; Lonsdorf, Elizabeth; Schaeffer, Jennifer; Russell, Jamie; Hopkins, William D.

    2015-01-01

    A number of factors have been proposed to influence within and between species variation in handedness in non-human primates. In the initial study, we assessed the influence of grip morphology on hand use for simple reaching in a sample of 564 great apes including 49 orangutans Pongo pygmaeus, 66 gorillas Gorilla gorilla, 354 chimpanzees Pan troglodytes and 95 bonobos Pan paniscus. Overall, we found a significant right hand bias for reaching. We also found a significant effect of the grip morphology of hand use. Grasping with the thumb and index finger was more prevalent in the right compared to left hand in all four species. There was no significant sex effect on the patterns of handedness. In a subsample of apes, we also compared consistency in hand use for simple reaching with previously published data on a task that measures handedness for bimanual actions. We found that the ratio of subjects with consistent right compared to left hand use was more prevalent in bonobos, chimpanzees and gorillas but not orangutans. However, for all species, the proportion of subjects with inconsistent hand preferences between the tasks was relatively high suggesting some measures may be more sensitive in assessing handedness than others. PMID:26635693

  1. Project Hand-Up. Helping Adolescents Needing Direction-Unlimited Partnership (HAND-UP): Stimulating Coordination and Linkage between Occupational Work Adjustment Programs and the Job Training Partnership Act (JTPA). Final Report.

    ERIC Educational Resources Information Center

    Ohio State Dept. of Education, Columbus. Div. of Vocational and Career Education.

    Project HAND-UP (Helping Adolescents Needing Direction-Unlimited Partnership) was a 2-year program to enhance dropout prevention services to at-risk youth by establishing a closer linkage between Job Training Partnership (JTPA)-Ohio and the Ohio Department of Education's Occupational Work Adjustment (OWA) programs. The project's major activities…

  2. From the Gleam in the Eye of an Engineer to a Dream Classroom: How Assistive Technology Products Move from Research and Development into the Hands of Children

    ERIC Educational Resources Information Center

    de St. Aubin, Shawn-Laree

    2010-01-01

    This article explains how Asssistive Technology products move from research and development into the hands of children. The assistive technology (AT) industry is maturing, with many exciting new technologies under development in university settings, by individual inventors and engineers, and by leading AT and information technology (IT) companies.…

  3. From the Gleam in the Eye of an Engineer to a Dream Classroom: How Assistive Technology Products Move from Research and Development into the Hands of Children

    ERIC Educational Resources Information Center

    de St. Aubin, Shawn-Laree

    2010-01-01

    This article explains how Asssistive Technology products move from research and development into the hands of children. The assistive technology (AT) industry is maturing, with many exciting new technologies under development in university settings, by individual inventors and engineers, and by leading AT and information technology (IT) companies.…

  4. Eye pain

    MedlinePlus

    Ophthalmalgia; Pain - eye ... Pain in the eye can be an important symptom of a health problem. Make sure you tell your health care provider if you have eye pain that does not go away. Tired eyes or ...

  5. Compound measure of hand-foot-eye preference masked opposite turning behavior in healthy right-handers and non-right-handers: technical comment on Mohr et al. (2003).

    PubMed

    Mohr, C; Bracha, H S

    2004-10-01

    A previous article reported opposite turning behavior in right-handers and non-right-handers (C. Mohr. T. Landis, H. S. Bracha, & P. Brugger, 2003). This observation appears contradictory to the 1st study on long-term spontaneous turning behavior in healthy participants (H. S. Bracha, D. J. Seitz, J. Otemaa, & S. D. Click, 1987). These latter authors found a complex interaction between hemispheric dominance, preferred turning side, and sex. C. Mohr et al. (2003) argued that the differentiation of the population in hemisphere-dominant groups by a compound measure of hand-foot-eye preference might have masked their recent finding. Thus, this commentary presents a reanalysis of the original data set (H. S. Bracha et al., 1987). Replicating recent observation, right-handers preferred left-sided turns; and non-righthanders, right-sided turns. This replication strengthens the proposition that handedness and turning behavior might depend on interhemispheric dopamine asymmetries. Copyright 2004 APA.

  6. Hawk-Eyes on Science and in Space

    NASA Astrophysics Data System (ADS)

    Durow, Lillie

    2017-08-01

    For more than ten years the successful and well received outreach programs, Hawk-Eyes On Science and Hawk-Eyes in Space, have brought the excitement of science demonstrations to Iowans of all ages. However, the creation of a successful, sustainable outreach program requires the coordination of many aspects. In many respects, the demonstrations and hands-on activities are of secondary importance when weighed against the problems of funding, transportation, staffing, etc. In addition to showing examples of demonstrations that we use, I will also focus on a few of the problems and some of the solutions that we have found while coordinating our long running outreach programs at the University of Iowa Department of Physics and Astronomy.

  7. Dextrous robot hands

    NASA Technical Reports Server (NTRS)

    Venkataraman, Subramanian T. (Editor); Iberall, Thea (Editor)

    1990-01-01

    Recent studies of human hand function and their implications for the design of robot hands are discussed in reviews and reports. Topics addressed include human grasp choice and robotic grasp analysis, opposition space and human prehension, coordination in normal and prosthetic reaching, and intelligent exploration by the human hand. Consideration is given to a task-oriented dextrous manipulation architecture, the control architecture for the Belgrade/USC hand, the analysis of multifingered grasping and manipulation, and tactile sensing for shape interpretation. Diagrams, graphs, and photographs are provided.

  8. Dextrous robot hands

    NASA Technical Reports Server (NTRS)

    Venkataraman, Subramanian T. (Editor); Iberall, Thea (Editor)

    1990-01-01

    Recent studies of human hand function and their implications for the design of robot hands are discussed in reviews and reports. Topics addressed include human grasp choice and robotic grasp analysis, opposition space and human prehension, coordination in normal and prosthetic reaching, and intelligent exploration by the human hand. Consideration is given to a task-oriented dextrous manipulation architecture, the control architecture for the Belgrade/USC hand, the analysis of multifingered grasping and manipulation, and tactile sensing for shape interpretation. Diagrams, graphs, and photographs are provided.

  9. Eye Diseases

    MedlinePlus

    ... the back of the eye Macular degeneration - a disease that destroys sharp, central vision Diabetic eye problems ... defense is to have regular checkups, because eye diseases do not always have symptoms. Early detection and ...

  10. Eye Injuries

    MedlinePlus

    The structure of your face helps protect your eyes from injury. Still, injuries can damage your eye, sometimes severely enough that you could lose your vision. Most eye injuries are preventable. If you play sports or ...

  11. Eye Cancer

    MedlinePlus

    Cancer of the eye is uncommon. It can affect the outer parts of the eye, such as the eyelid, which are made up ... adults are melanoma and lymphoma. The most common eye cancer in children is retinoblastoma, which starts in ...

  12. Eye Allergies

    MedlinePlus

    ... Sep. 01, 2016 Eye allergies, also called allergic conjunctivitis, are quite common. They occur when the eyes ... can tear and burn. Unlike other kinds of conjunctivitis, eye allergies are not spread from person to ...

  13. Watery eyes

    MedlinePlus

    ... the most common causes of excess tearing is dry eyes . Drying causes the eyes to become uncomfortable, which stimulates the body to produce too many tears. One of the main tests for tearing is to check whether the eyes ...

  14. Using a continuous index of laterality to determine how laterality is related to interhemispheric transfer and bimanual coordination in children.

    PubMed

    Fagard, Jacqueline; Corroyer, Denis

    2003-07-01

    We sought to determine whether laterality is related to interhemispheric transfer and bimanual coordination during development. Children between 3 and 8 years of age were observed. In the first part of the experiment, we devised a continuous index to order the subjects according to their laterality. The laterality index included evaluation of hand and eye preference, and the right-left performance difference. In the second part of the experiment, we used this single index to determine whether laterality is related to interhemispheric transfer and bimanual coordination. Interhemispheric transfer was assessed by means of two tactile transfer tasks and one visuo-manual transfer task. We assessed bimanual coordination using the tapping task and the bimanual crank-rotation task. Results showed that right- and left-hand writers overlap on certain measures of laterality. They confirmed the improvement of interhemispheric transfer at around age 5 years, earlier progress in bimanual coordination with mirror than with parallel movements, and the existence of a relationship between visuo-manual interhemispheric transfer and bimanual coordination. The laterality index was not related to interhemispheric transfer, but it was related to the younger subjects' performance on the bimanual crank-rotation task: the less right handed, the better the bimanual coordination. In addition, on the same bimanual task, crossed hand-eye laterality was associated with better performance. Copyright 2003 Wiley Periodicals, Inc. Dev Psychobiol 43: 44-56, 2003.

  15. 'Always the guiding hand': parents' accounts of the long-term implications of developmental co-ordination disorder for their children and families.

    PubMed

    Stephenson, E A; Chesson, R A

    2008-05-01

    There has been little investigation of the long-term implications of developmental co-ordination disorder (DCD) and, particularly, its impact on families. This is despite the prevalence of the disorder (4.5% to 6%) of the child population, and the high rates of referral to occupational therapy departments. The study reported here was part of an evaluation of an innovative screening clinic for the assessment of children with DCD. Within the case study approach of the evaluation, questionnaires, including open-end questions, were sent to 70 families. All had attended the screening clinic 6 years earlier and had little subsequent contact with the occupational therapy service. Semi-structured interviews were held with 12 mothers who volunteered to participate. These enabled specific issues raised in the questionnaires to be explored in greater depth. Interviews were audiotaped and full text transcripts produced for analysis. Over half the questionnaires were returned despite the length of time elapsed since hospital contact. Parents who responded reported a high persistence of problems in their children. Difficulties spanned motor and academic performance, emotional/behavioural responses and social interaction. Twenty-eight children (80%) of respondents were reported as having difficulties in three or more areas. Bullying was a commonly identified problem. At interview mothers spoke at length about their experiences and reported feeling stressed and distressed. Mothers reported a lack of support and expressed feelings of isolation. They said that their time investment in their child with DCD had pronounced effects on themselves and other family members. Specifically they highlighted time spent fighting the system, primarily for educational support. The study suggests a need for occupational therapists to reframe their current ideas regarding service provision, with improved support for families, increased interagency working and more service-user involvement.

  16. Modeling the Scheduling of Eye Movements and Manual Responses in Performing a Sequence of Discrete Tasks

    NASA Technical Reports Server (NTRS)

    Wu, Shu-Chieh; Remington, Roger W.; Lewis, Richard

    2006-01-01

    Common tasks in daily life are often accomplished by a sequence of actions that interleave information acquisition through the eyes and action execution by the hands. How are eye movements coordinated with the release of manual responses and how may their coordination be represented at the level of component mental operations? We have previously presented data from a typing-like task requiring separate choice responses to a series of five stimuli. We found a consistent pattern of results in both motor and ocular timing, and hypothesized possible relationships among underlying components. Here we report a model of that task, which demonstrates how the observed timing of eye movements to successive stimuli could be accounted for by assuming systems: an open-loop system generating saccades at a periodic rate, and a closed-loop system commanding a saccade based on stimulus processing. We relate this model to models of reading and discuss the motivation for dual control.

  17. Modeling the Scheduling of Eye Movements and Manual Responses in Performing a Sequence of Discrete Tasks

    NASA Technical Reports Server (NTRS)

    Wu, Shu-Chieh; Remington, Roger W.; Lewis, Richard

    2006-01-01

    Common tasks in daily life are often accomplished by a sequence of actions that interleave information acquisition through the eyes and action execution by the hands. How are eye movements coordinated with the release of manual responses and how may their coordination be represented at the level of component mental operations? We have previously presented data from a typing-like task requiring separate choice responses to a series of five stimuli. We found a consistent pattern of results in both motor and ocular timing, and hypothesized possible relationships among underlying components. Here we report a model of that task, which demonstrates how the observed timing of eye movements to successive stimuli could be accounted for by assuming systems: an open-loop system generating saccades at a periodic rate, and a closed-loop system commanding a saccade based on stimulus processing. We relate this model to models of reading and discuss the motivation for dual control.

  18. Integration of visual and somatosensory target information in goal-directed eye and arm movements.

    PubMed

    Neggers, S F; Bekkering, H

    1999-03-01

    In this study, we compared separate and coordinated eye and hand movements towards visual or somatosensory target stimuli in a dark room, where no visual position information about the hand could be obtained. Experiment 1 showed that saccadic reaction times (RTs) were longer when directed to somatosensory targets than when directed to visual targets in both single- and dual-task conditions. However, for hand movements, this pattern was only found in the dual-task condition and not in the single-task condition. Experiment 1 also showed that correlations between saccadic and hand RTs were significantly higher when directed towards somatosensory targets than when directed towards visual targets. Importantly, experiment 2 indicated that this was not caused by differences in processing times at a perceptual level. Furthermore, hand-pointing accuracy was found to be higher when subjects had to move their eyes as well (dual task) compared to a single-task hand movement. However, this effect was more pronounced for movements to visual targets than to somatosensory targets. A schematic model of sensorimotor transformations for saccadic eye and goal-directed hand movements is proposed and possible shared mechanisms of the two motor systems are discussed.

  19. Claw hand

    MedlinePlus

    Ulnar nerve palsy - claw hand; Ulnar nerve dysfunction - claw hand; Ulnar claw ... Someone can be born with claw hand (congenital), or they can develop it because of certain disorders, such as nerve injury.

  20. Self-development of visual space perception by learning from the hand

    NASA Astrophysics Data System (ADS)

    Chung, Jae-Moon; Ohnishi, Noboru

    1998-10-01

    Animals have been considered to develop ability for interpreting images captured on their retina by themselves gradually from their birth. For this they do not need external supervisor. We think that the visual function is obtained together with the development of hand reaching and grasping operations which are executed by active interaction with environment. On the viewpoint of hand teaches eye, this paper shows how visual space perception is developed in a simulated robot. The robot has simplified human-like structure used for hand-eye coordination. From the experimental results it may be possible to validate the method to describe how visual space perception of biological systems is developed. In addition the description gives a way to self-calibrate the vision of intelligent robot based on learn by doing manner without external supervision.

  1. Detection of hand tremor in workers exposed to mercury vapor: a comparative study of three methods.

    PubMed

    Roels, H; Abdeladim, S; Braun, M; Malchaire, J; Lauwerys, R

    1989-08-01

    Hand tremor measurement was evaluated in a group of 54 male workers (mean age 38.5 years) exposed to mercury vapor (average duration of exposure 7.7 years) using an accelerometer test and two psychomotor tests (eye-hand coordination and hand steadiness). The results were compared with those obtained in a well-matched control group of 48 workers. The intensity of current mercury vapor exposure was rather moderate as reflected by the mean (geometric) levels of mercury in blood (2.4 micrograms/dl) and in urine (63 micrograms/g creatinine). The hand steadiness test and eye-hand coordination test revealed preclinical alterations in postural and intentional tremor, whereas the changes evidenced by the accelerometer test were not statistically significant. Furthermore the practical advantage of the psychomotor tests over the accelerometer test makes them most appropriate for the early detection of mercury-induced hand tremor. The present study also suggests that young adults (less than 21 years) may be more susceptible to the neurotoxic effect of mercury vapor.

  2. Hand transplantation.

    PubMed

    Amer, Hatem; Carlsen, Brian T; Dusso, Jennifer L; Edwards, Brooks S; Moran, Steven L

    2011-05-01

    The first successful hand transplant was performed in 1998, opening up a new possibility for patients who have suffered mutilating hand injuries. Since then, more than 60 such procedures have been performed throughout the world. This article describes the evolution of hand transplantation, outcomes of patients listed in the International Registry of Hand and Composite Tissue Transplantation, and ethical issues involved in hand transplantation. It also describes the hand transplantation program at Mayo Clinic, which was established in 2010.

  3. Alcohol badly affects eye movements linked to steering, providing for automatic in-car detection of drink driving.

    PubMed

    Marple-Horvat, Dilwyn E; Cooper, Hannah L; Gilbey, Steven L; Watson, Jessica C; Mehta, Neena; Kaur-Mann, Daljit; Wilson, Mark; Keil, Damian

    2008-03-01

    Driving is a classic example of visually guided behavior in which the eyes move before some other action. When approaching a bend in the road, a driver looks across to the inside of the curve before turning the steering wheel. Eye and steering movements are tightly linked, with the eyes leading, which allows the parts of the brain that move the eyes to assist the parts of the brain that control the hands on the wheel. We show here that this optimal relationship deteriorates with levels of breath alcohol well within the current UK legal limit for driving. The eyes move later, and coordination reduces. These changes lead to bad performance and can be detected by an automated in-car system, which warns the driver is no longer fit to drive.

  4. The cell adhesion molecules Echinoid and Friend of Echinoid coordinate cell adhesion and cell signaling to regulate the fidelity of ommatidial rotation in the Drosophila eye.

    PubMed

    Fetting, Jennifer L; Spencer, Susan A; Wolff, Tanya

    2009-10-01

    Directed cellular movements are a universal feature of morphogenesis in multicellular organisms. Differential adhesion between the stationary and motile cells promotes these cellular movements to effect spatial patterning of cells. A prominent feature of Drosophila eye development is the 90 degrees rotational movement of the multicellular ommatidial precursors within a matrix of stationary cells. We demonstrate that the cell adhesion molecules Echinoid (Ed) and Friend of Echinoid (Fred) act throughout ommatidial rotation to modulate the degree of ommatidial precursor movement. We propose that differential levels of Ed and Fred between stationary and rotating cells at the initiation of rotation create a permissive environment for cell movement, and that uniform levels in these two populations later contribute to stopping the movement. Based on genetic data, we propose that ed and fred impart a second, independent, ;brake-like' contribution to this process via Egfr signaling. Ed and Fred are localized in largely distinct and dynamic patterns throughout rotation. However, ed and fred are required in only a subset of cells - photoreceptors R1, R7 and R6 - for normal rotation, cells that have only recently been linked to a role in planar cell polarity (PCP). This work also provides the first demonstration of a requirement for cone cells in the ommatidial rotation aspect of PCP. ed and fred also genetically interact with the PCP genes, but affect only the degree-of-rotation aspect of the PCP phenotype. Significantly, we demonstrate that at least one PCP protein, Stbm, is required in R7 to control the degree of ommatidial rotation.

  5. Hand hygiene.

    PubMed

    Bolon, Maureen

    2011-03-01

    The toll of health care-associated infections on patients and the seeming ease of the procedure thought best able to prevent them have focused a spotlight onto hand hygiene performance. Poor performance of hand hygiene by health care workers inspires outrage in the general public. Much is understood regarding barriers to and motivators of hand hygiene performance. Guidelines encouraging use of alcohol-based hand hygiene agents have facilitated hand hygiene improvement efforts. These efforts and evidence that improved hand hygiene performance is associated with a reduction in health care-associated infections should encourage those in the hand hygiene campaigns.

  6. Tie My Hands, Tie My Eyes

    ERIC Educational Resources Information Center

    Ambrosini, Ettore; Sinigaglia, Corrado; Costantini, Marcello

    2012-01-01

    Previous studies have demonstrated that motor abilities allow us not only to execute our own actions and to predict their consequences, but also to predict others' actions and their consequences. But just how deeply are motor abilities implicated in action observation? If an observer is prevented from acting while witnessing others' actions, will…

  7. Uncalibrated Eye-in-Hand Visual Servoing

    DTIC Science & Technology

    2003-11-01

    interaction models in visual servoing. IEEE Transactions on Robotics and Automation 15(2):350–357. Baeten, J., and De Schutter, J. 1999. Improving...improvements in the stability analysis of a new class of model-free visual servoing methods. IEEE Transactions on Robotics and Au- tomation 18(2):176–186. Oh...P. Y., and Allen, P. K. 2001. Visual servoing by partition- ing degrees of freedom. IEEE Transactions on Robotics and Automation 17(1):1–17

  8. Tie My Hands, Tie My Eyes

    ERIC Educational Resources Information Center

    Ambrosini, Ettore; Sinigaglia, Corrado; Costantini, Marcello

    2012-01-01

    Previous studies have demonstrated that motor abilities allow us not only to execute our own actions and to predict their consequences, but also to predict others' actions and their consequences. But just how deeply are motor abilities implicated in action observation? If an observer is prevented from acting while witnessing others' actions, will…

  9. Sensorimotor performance as a function of eye dominance and handedness.

    PubMed

    Coren, S

    1999-04-01

    Performance on a speeded target striking task was significantly associated with eye dominance and handedness for a sample of 30 subjects. They showed the expected higher performance with the dominant hand but also showed an effect of eye of input. Highest performance was obtained with binocular viewing, next best used the dominant eye, and poorest performance the nondominant eye. Effects were additive with no interaction between hand and eye dominance.

  10. Vision research: losing sight of eye dominance.

    PubMed

    Carey, D P

    2001-10-16

    Most people prefer to use their right eye for viewing. New evidence reveals that this dominance is much more plastic than that for one hand or foot: it changes from one eye to the other depending on angle of gaze. Remarkably, sighting dominance depends on the hand being directed towards the visual target.

  11. Your Eyes

    MedlinePlus

    ... the eye and keeps it healthy. previous continue Light, Lens, Action These next parts are really cool, ... the eye. previous continue Rods and Cones Process Light The retina uses special cells called rods and ...

  12. Eye Anatomy

    MedlinePlus

    ... News About Us Donate In This Section Eye Anatomy en Español email Send this article to a ... You at Risk For Glaucoma? Childhood Glaucoma Eye Anatomy Five Common Glaucoma Tests Glaucoma Facts and Stats ...

  13. Eye emergencies

    MedlinePlus

    ... by common household products such as cleaning solutions, garden chemicals, solvents, or other types of chemicals. Fumes ... in the eye with a ball, such as indoor racket sports Images Eye First aid kit References ...

  14. Healthy Eyes

    MedlinePlus

    ... please turn Javascript on. Healthy Eyes Maintaining Your Vision Click for more information Taking good care of ... are qualified to perform eye exams. Aging and Vision Changes As you age, it is normal to ...

  15. Eye Emergencies

    MedlinePlus

    ... The Marfan Foundation Marfan & Related Disorders What is Marfan Syndrome? What are Related Disorders? What are the Signs? ... Emergencies Eye Emergencies Lung Emergencies Surgeries Eye Emergencies Marfan syndrome significantly increases your risk of retinal detachment, a ...

  16. Your Eyes

    MedlinePlus

    ... the eye and keeps it healthy. previous continue Light, Lens, Action These next parts are really cool, ... the eye. previous continue Rods and Cones Process Light The retina uses special cells called rods and ...

  17. Saccadic movements of the eyes in children with attention deficit and hyperactivity syndrome.

    PubMed

    Damyanovich, E V; Baziyan, B Kh; Sagalov, M V; Kumskova, G A

    2013-11-01

    Saccadic movements of the eyes were analyzed in children with the attention deficit and hyperactivity syndrome. Saccadic movements of the eyes were recorded by a special method for their isolated registration without involvement of the head and in coordination tests (eye-head, eye-hand, and eye-head-hand). Comparative analysis of saccadic movements in children with attention deficit and hyperactivity and in normal subjects was carried out. Saccades recorded in each participant in complex tests with one or two additional motor acts, such as movements of the head and hand, were compared and the changes were analyzed for the group. Children with attention deficit and hyperactivity syndrome had problem with gaze fixation on the peripheral target after the end of the saccade and these changes augmented in more complex tasks with one or two additional acts. This could be due to discrepancy between the difficulty of the task and the potentialities of the frontal cortex, more immature in these patients than in healthy children. The changes could form the objective base for disorders in the formation of reading and writing habits, often observed in children with attention deficit and hyperactivity syndrome.

  18. Magnetic eye tracking in mice

    PubMed Central

    Payne, Hannah L

    2017-01-01

    Eye movements provide insights about a wide range of brain functions, from sensorimotor integration to cognition; hence, the measurement of eye movements is an important tool in neuroscience research. We describe a method, based on magnetic sensing, for measuring eye movements in head-fixed and freely moving mice. A small magnet was surgically implanted on the eye, and changes in the magnet angle as the eye rotated were detected by a magnetic field sensor. Systematic testing demonstrated high resolution measurements of eye position of <0.1°. Magnetic eye tracking offers several advantages over the well-established eye coil and video-oculography methods. Most notably, it provides the first method for reliable, high-resolution measurement of eye movements in freely moving mice, revealing increased eye movements and altered binocular coordination compared to head-fixed mice. Overall, magnetic eye tracking provides a lightweight, inexpensive, easily implemented, and high-resolution method suitable for a wide range of applications. PMID:28872455

  19. Cold Hands

    MedlinePlus

    ... you have a problem with the nerves or blood circulation or a problem with tissue damage in your hands or fingers. ... of causes. Having cold hands could signal a problem with your blood circulation or the blood vessels in your hands. Make ...

  20. Chapped hands

    MedlinePlus

    ... wind Avoid washing hands with hot water Limit hand washing as much as possible while maintaining good hygiene Try to keep the air in your home humid Use mild soaps or non-soap cleansers Use ... on your hands regularly, especially if you live in a dry ...

  1. [Hand osteoarthritis].

    PubMed

    Šenolt, Ladislav

    Hand osteoarthritis (OA) is a common chronic disorder causing pain and limitation of mobility of affected joints. The prevalence of hand OA increases with age and more often affects females. Clinical signs obviously do not correlate with radiographic findings - symptomatic hand OA affects approximately 26 % of adult subjects, but radiographic changes can be found in up to two thirds of females and half of males older than 55 years.Disease course differ among individual patients. Hand OA is a heterogeneous disease. Nodal hand OA is the most common subtype affecting interphalangeal joints, thumb base OA affects first carpometacarpal joint. Erosive OA represents a specific subtype of hand OA, which is associated with joint inflammation, more pain, functional limitation and erosive findings on radiographs.Treatment of OA is limited. Analgesics and nonsteroidal anti-inflammatory drugs are the only agents reducing symptoms. New insights into the pathogenesis of disease should contribute to the development of novel effective treatment of hand OA.

  2. Monocular tool control, eye dominance, and laterality in New Caledonian crows.

    PubMed

    Martinho, Antone; Burns, Zackory T; von Bayern, Auguste M P; Kacelnik, Alex

    2014-12-15

    Tool use, though rare, is taxonomically widespread, but morphological adaptations for tool use are virtually unknown. We focus on the New Caledonian crow (NCC, Corvus moneduloides), which displays some of the most innovative tool-related behavior among nonhumans. One of their major food sources is larvae extracted from burrows with sticks held diagonally in the bill, oriented with individual, but not species-wide, laterality. Among possible behavioral and anatomical adaptations for tool use, NCCs possess unusually wide binocular visual fields (up to 60°), suggesting that extreme binocular vision may facilitate tool use. Here, we establish that during natural extractions, tool tips can only be viewed by the contralateral eye. Thus, maintaining binocular view of tool tips is unlikely to have selected for wide binocular fields; the selective factor is more likely to have been to allow each eye to see far enough across the midsagittal line to view the tool's tip monocularly. Consequently, we tested the hypothesis that tool side preference follows eye preference and found that eye dominance does predict tool laterality across individuals. This contrasts with humans' species-wide motor laterality and uncorrelated motor-visual laterality, possibly because bill-held tools are viewed monocularly and move in concert with eyes, whereas hand-held tools are visible to both eyes and allow independent combinations of eye preference and handedness. This difference may affect other models of coordination between vision and mechanical control, not necessarily involving tools. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Arm-trunk coordination as a measure of vestibulospinal efficiency.

    PubMed

    Sibindi, Tafadzwa M; Krasovsky, Tal; Feldman, Anatol G; Dannenbaum, Elizabeth; Zeitouni, Anthony; Levin, Mindy F

    2013-01-01

    When arm and trunk segments are involved in reaching for objects within arm's reach, vestibulospinal pathways compensate for trunk motion influence on arm movement. This compensatory arm-trunk synergy is characterised by a gain coefficient of 0 to 1. Vestibular patients have less efficient arm-trunk synergies and lower gains. To assess the clinical usefulness of the gain measure, we used a portable ultrasound-based device to characterize arm-trunk coordination deficits in vestibular patients. Arm-trunk coordination without vision was measured in a Stationary Hand Task where hand position was maintained during trunk movement, and a Reaching Task with and without trunk motion. Twenty unilateral vestibular patients and 16 controls participated. For the Stationary Hand task, patient gains ranged from g=0.94 (good compensation) to 0.31 (poor compensation) and, on average, were lower than in controls (patients: 0.67 ± 0.19; controls: 0.85 ± 0.07; p< 0.01). Gains were significantly correlated with clinical tests (Sensory Organization; r=0.62, p< 0.01, Foam Romberg Eyes Closed; r=0.65, p< 0.01). For the Reaching Task, blocking trunk movement during reaching modified hand position significantly more in patients (8.2 ± 4.3 cm) compared to controls (4.5 ± 1.7 cm, p< 0.02) and the amount of hand position deviation was correlated with the degree of vestibular loss in a sub-group (n=14) of patients. Measurement of the Stationary Task arm-trunk gain and hand deviations during the Reaching Task can help characterize sensorimotor problems in vestibular-deficient patients and track recovery following therapeutic interventions. The ultrasound-based portable device is suitable for measuring vestibulospinal deficits in arm-trunk coordination in a clinical setting.

  4. Eye development.

    PubMed

    Baker, Nicholas E; Li, Ke; Quiquand, Manon; Ruggiero, Robert; Wang, Lan-Hsin

    2014-06-15

    The eye has been one of the most intensively studied organs in Drosophila. The wealth of knowledge about its development, as well as the reagents that have been developed, and the fact that the eye is dispensable for survival, also make the eye suitable for genetic interaction studies and genetic screens. This article provides a brief overview of the methods developed to image and probe eye development at multiple developmental stages, including live imaging, immunostaining of fixed tissues, in situ hybridizations, and scanning electron microscopy and color photography of adult eyes. Also summarized are genetic approaches that can be performed in the eye, including mosaic analysis and conditional mutation, gene misexpression and knockdown, and forward genetic and modifier screens.

  5. Robot Hand

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Robots are limited only by the dexterity of the hand. Dr. Salisbury, in conjunction with Stanford, Caltech and Jet Propulsion Laboratory, developed the Salisbury Hand which has three, three-jointed human-like fingers. The tips are covered with a resilient, high friction material for gripping. The robot hand can manipulate objects by finger motion, and adapts to different aims. Advanced software allows the hand to interpret information from fingertip sensors. Further development is expected. A company has been formed to reproduce the device; copies have been delivered to several laboratories.

  6. Diabetes eye exams

    MedlinePlus

    Diabetic retinopathy - eye exams; Diabetes - eye exams; Glaucoma - diabetic eye exam; Macular edema - diabetic eye exam ... if the doctor who takes care of your diabetes checks your eyes, you need an eye exam ...

  7. Bimanual-vertical hand movements.

    PubMed

    Kwon, Jay C; Cohen, Matthew L; Williamson, John; Burtis, Brandon; Heilman, Kenneth M

    2011-07-01

    Patients often demonstrate attentional and action-intentional biases in both the transverse and coronal planes. In addition, when making forelimb movements in the transverse plane, normal participants also have spatial and magnitude asymmetries, but forelimb spatial asymmetries have not been studied in coronal space. Thus, to learn if when normal people make vertical movements they have right-left spatial and magnitude biases, seventeen healthy, blindfolded volunteers had their hands (holding pens) placed vertically in their midsagittal plane, 10 inches apart, on pieces of paper positioned above, below, and at eye-level. Participants were asked to move their hands together vertically and meet in the middle. Participants demonstrated less angular deviation in the below-eye condition than in the other spatial conditions, when moving down than up, and with their right than left hand. Movements toward eye level from upper or lower space were also more accurate than movements in the other directions. Independent of hand, lines were longer with downward than upward movements and the right hand moved more distance than the left. These attentional-intentional asymmetries may be related to gravitational force, hand-hemispheric dominance, and spatial "where" asymmetries; however, the mechanisms accounting for these asymmetries must be ascertained by future research.

  8. (Robotic hands)

    SciTech Connect

    Mann, R.C.

    1988-09-23

    The traveler attended the International Workshop on Robot Hands at the Palace Hotel in Dubrovnik, Yugoslavia. The traveler presented a lecture on An integrated sensor system for the ORNL mobile robot.'' The traveler obtained important information on current R D efforts in multi-fingered robot hands and object recognition using touch sensing.

  9. Eye Health

    PubMed Central

    Connell, A. M. S.

    1988-01-01

    The status of eye care in the Caribbean is discussed. Methods of primary eye care providers at all levels from primary to tertiary in the region are presented against a background of the major causes of blindness, cataract, glaucoma, and diabetic retinopathy. Epidemiological surveys examining prevalence, risk factors, and intervention programs are being undertaken. PMID:3404562

  10. Eyes - bulging

    MedlinePlus

    ... emotional support is important. When to Contact a Medical Professional Call your health care provider if: You have bulging eyes and the cause has not yet been diagnosed. Bulging eyes are accompanied by other symptoms. ... The provider will ask about your medical history and do a physical exam. Some questions ...

  11. Robotic Hand

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Omni-Hand was developed by Ross-Hime Designs, Inc. for Marshall Space Flight Center (MSFC) under a Small Business Innovation Research (SBIR) contract. The multiple digit hand has an opposable thumb and a flexible wrist. Electric muscles called Minnacs power wrist joints and the interchangeable digits. Two hands have been delivered to NASA for evaluation for potential use on space missions and the unit is commercially available for applications like hazardous materials handling and manufacturing automation. Previous SBIR contracts resulted in the Omni-Wrist and Omni-Wrist II robotic systems, which are commercially available for spray painting, sealing, ultrasonic testing, as well as other uses.

  12. Mixed Body/Hand Reference Frame for Reaching in 3D Space in Macaque Parietal Area PEc.

    PubMed

    Piserchia, Valentina; Breveglieri, Rossella; Hadjidimitrakis, Kostas; Bertozzi, Federica; Galletti, Claudio; Fattori, Patrizia

    2017-03-01

    The neural correlates of coordinate transformations from vision to action are expressed in the activity of posterior parietal cortex (PPC). It has been demonstrated that among the medial-most areas of the PPC, reaching targets are represented mainly in hand-centered coordinates in area PE, and in eye-centered, body-centered, and mixed body/hand-centered coordinates in area V6A. Here, we assessed whether neurons of area PEc, located between V6A and PE in the medial PPC, encode targets in body-centered, hand-centered, or mixed frame of reference during planning and execution of reaching. We studied 104 PEc cells in 3 Macaca fascicularis. The animals performed a reaching task toward foveated targets located at different depths and directions in darkness, starting with the hand from 2 positions located at different depths, one next to the trunk and the other far from it. We show that most PEc neurons encoded targets in a mixed body/hand-centered frame of reference. Although the effect of hand position was often rather strong, it was not as strong as reported previously in area PE. Our results suggest that area PEc represents an intermediate node in the gradual transformation from vision to action that takes place in the reaching network of the dorsomedial PPC. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  13. Hand Eczema

    PubMed Central

    Agarwal, Uma Shankar; Besarwal, Raj Kumar; Gupta, Rahul; Agarwal, Puneet; Napalia, Sheetal

    2014-01-01

    Hand eczema is often a chronic, multifactorial disease. It is usually related to occupational or routine household activities. Exact etiology of the disease is difficult to determine. It may become severe enough and disabling to many of patients in course of time. An estimated 2-10% of population is likely to develop hand eczema at some point of time during life. It appears to be the most common occupational skin disease, comprising 9-35% of all occupational diseases and up to 80% or more of all occupational contact dermatitis. So, it becomes important to find the exact etiology and classification of the disease and to use the appropriate preventive and treatment measures. Despite its importance in the dermatological practice, very few Indian studies have been done till date to investigate the epidemiological trends, etiology, and treatment options for hand eczema. In this review, we tried to find the etiology, epidemiology, and available treatment modalities for chronic hand eczema patients. PMID:24891648

  14. Hand aperture patterns in prehension.

    PubMed

    Bongers, Raoul M; Zaal, Frank T J M; Jeannerod, Marc

    2012-06-01

    Although variations in the standard prehensile pattern can be found in the literature, these alternative patterns have never been studied systematically. This was the goal of the current paper. Ten participants picked up objects with a pincer grip. Objects (3, 5, or 7cm in diameter) were placed at 30, 60, 90, or 120cm from the hands' starting location. Usually the hand was opened gradually to a maximum immediately followed by hand closing, called the standard hand opening pattern. In the alternative opening patterns the hand opening was bumpy, or the hand aperture stayed at a plateau before closing started. Two participants in particular delayed the start of grasping with respect to start of reaching, with the delay time increasing with object distance. For larger object distances and smaller object sizes, the bumpy and plateau hand opening patterns were used more often. We tentatively concluded that the alternative hand opening patterns extended the hand opening phase, to arrive at the appropriate hand aperture at the appropriate time to close the hand for grasping the object. Variations in hand opening patterns deserve attention because this might lead to new insights into the coordination of reaching and grasping.

  15. Eye point-of-regard system

    NASA Technical Reports Server (NTRS)

    Jex, H. R.

    1971-01-01

    System measures intersection of line of sight and eye point of regard /EPR/ for a human operator in visual scanning system. Device measures two head to reference angles with EPR system and adds them with eye to head angles, yielding a dc signal proportional to picture plane coordinates.

  16. Black Eye

    MedlinePlus

    ... Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide Academy Publications EyeNet Ophthalmology Information for: International Ophthalmologists Media Medical Students Patients and Public Technicians and Nurses ...

  17. Eye Symptoms

    MedlinePlus

    ... Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide Academy Publications EyeNet Ophthalmology Information for: International Ophthalmologists Media Medical Students Patients and Public Technicians and Nurses ...

  18. Eye Infections

    MedlinePlus

    ... become red, he probably has a condition called conjunctivitis . Also known as pinkeye, this inflammation, which can be painful and itchy, ... bacteria, antibiotic eye drops are the usual treatment. Conjunctivitis caused by viruses should not be treated with ...

  19. Eye dominance in children: a longitudinal study.

    PubMed

    Dellatolas, G; Curt, F; Dargent-Paré, C; De Agostini, M

    1998-05-01

    In a sample of 807 normal preschool children aged from 3 to 6, examined eye dominance was not associated with the declared eye dominance of their parents. Forty percent of the children showed left-eyedness. Eyedness was associated with handedness and not significantly related to age group or sex. A strong relationship between the answers of the two parents concerning eye preference was observed. Two hundred forty-four children were followed-up for 2 years. The examinations were carried out once every 6 months. Two thirds of the children showed perfect stability in eye dominance. There was some evidence that stability in eye use tends to increase with age and to be lower in left-handed children with left-handed parents. There is, at present, very little evidence of a positive association between eye dominance in parents and that in their children.

  20. Preventing Eye Injuries

    MedlinePlus

    ... Stories Español Eye Health / Eye Health A-Z Eye Injuries Sections Preventing Eye Injuries Recognizing and Treating ... Infographic Five Steps to Safer Champagne Celebrations Preventing Eye Injuries Reviewed by: Brenda Pagan-Duran MD Mar. ...

  1. Temporal coordination between performing musicians.

    PubMed

    Loehr, Janeen D; Palmer, Caroline

    2011-11-01

    Many common behaviours require people to coordinate the timing of their actions with the timing of others' actions. We examined whether representations of musicians' actions are activated in coperformers with whom they must coordinate their actions in time and whether coperformers simulate each other's actions using their own motor systems during temporal coordination. Pianists performed right-hand melodies along with simple or complex left-hand accompaniments produced by themselves or by another pianist. Individual performers' preferred performance rates were measured in solo performance of the right-hand melody. The complexity of the left-hand accompaniment influenced the temporal grouping structure of the right-hand melody in the same way when it was performed by the self or by the duet partner, providing some support for the action corepresentation hypothesis. In contrast, accompaniment complexity had little influence on temporal coordination measures (asynchronies and cross-correlations between parts). Temporal coordination measures were influenced by a priori similarities between partners' preferred rates; partners who had similar preferred rates in solo performance were better synchronized and showed mutual adaptation to each other's timing during duet performances. These findings extend previous findings of action corepresentation and action simulation to a task that requires precise temporal coordination of independent yet simultaneous actions.

  2. Occupational eye injuries in Finland.

    PubMed

    Saari, K M; Parvi, V

    1984-01-01

    In Finland 11.9% of all industrial accidents in 1973 were eye injuries including superficial eye injuries (79.2%), ultraviolet burns of the cornea (3.9%), eye burns (3.6%), blunt ocular trauma (2,5%), wounds (2.4%), and post-traumatic infections (5.8%). Eye injuries constituted 34.3% of all industrial accidents which needed only ambulatory treatment and 17.5% of all industrial accidents causing an absence for 1-2 days. In 1981 2.1% of all compensated industrial accidents (incapacity for work 3 days or more) were eye injuries. Most compensated eye injuries occurred in manufacturing and in construction work (80.4%) and 8.5% occurred in agriculture. The annual incidence rates of compensated accidents to the eyes (accidents X 1 000/number of employees) were highest in several branches of metal industry (4.96-6.88), excavating and foundation work (6.88), and in logging (5.64). Compensated eye injuries were caused by machines (32.8%), hand tools (25.6%), other equipment and constructions (4.8%), work environment (23.6%), chemical substances (10.8%), and other accidents (2.3%).

  3. Hand reanimation.

    PubMed

    Dafydd, Hywel; Lin, Chih-Hung

    2014-03-01

    Brachial plexus disruption, major traumatic amputations, and Volkmann's contracture are all devastating injuries that present difficult reconstructive challenges. Advances in our understanding of nerve injury, regeneration, and refinement of microsurgical techniques have given rise to a number of therapeutic avenues over the last 4 decades. Hand reanimation aims to provide strength, stability, and mobility to a sensate hand. How this is achieved depends on a thorough understanding of the underlying pathophysiology, which in turn dictates what surgical modalities are suitable. Common to all reanimation procedures is the need to ensure full passive range of motion of the target joints prior to definitive surgery. Hand therapy is essential to prevent deleterious sequelae of injury, and to maximize rehabilitation following surgical reconstruction. Options for reanimation include nerve repair, nerve grafting, nerve transfer, tendon transfer, and free functioning muscle transfer.

  4. [Hand infections].

    PubMed

    Schiele, Philippe; Le Nen, Dominique

    2013-11-01

    Superficial and deep hand infections are frequent in general medical practice. Clinical examination is a crucial step for an adapted provided care. Most of the time, surgery is the only way to heal infections. However, in some cases (like bites), empiric antibiotherapy is first indicated to limit infection. Staphyloccocus aureus as well as Group Beta Streptococcus are the most frequently pathogenes associated with hand infections. Methicillin resistant S. Aureus must always be considered in the diagnoses. Whatever treatment is provided, clinical assessement must be repeated within two days. An early adaquated treatment prevent functional complications and in some cases death of the patients.

  5. 33 CFR 401.42 - Passing hand lines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... downbound vessel shall use its own hand lines, secured to the eye at the end of the mooring lines, by means... behind the splice of the eye; (3) At Iroquois Lock and Lock 8, Welland Canal, both upbound and downbound... to the eye of the No. 1 mooring wire by means of a bowline. (b) Mooring lines shall not be...

  6. 33 CFR 401.42 - Passing hand lines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... downbound vessel shall use its own hand lines, secured to the eye at the end of the mooring lines, by means... behind the splice of the eye; (3) At Iroquois Lock and Lock 8, Welland Canal, both upbound and downbound... to the eye of the No. 1 mooring wire by means of a bowline. (b) Mooring lines shall not be...

  7. 33 CFR 401.42 - Passing hand lines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... downbound vessel shall use its own hand lines, secured to the eye at the end of the mooring lines, by means... behind the splice of the eye; (3) At Iroquois Lock and Lock 8, Welland Canal, both upbound and downbound... to the eye of the No. 1 mooring wire by means of a bowline. (b) Mooring lines shall not be...

  8. How to Use Eye Ointments and Gels

    MedlinePlus

    How to Use Eye Ointments and GelsWash your hands thoroughly with soap and water. Avoid touching the tip of the tube against your eye or ... 0.6- to 1.25-centimeter) ribbon of ointment or gel into the pocket made by the ...

  9. Do the eyes scan dream images during rapid eye movement sleep? Evidence from the rapid eye movement sleep behaviour disorder model.

    PubMed

    Leclair-Visonneau, Laurène; Oudiette, Delphine; Gaymard, Bertrand; Leu-Semenescu, Smaranda; Arnulf, Isabelle

    2010-06-01

    Rapid eye movements and complex visual dreams are salient features of human rapid eye movement sleep. However, it remains to be elucidated whether the eyes scan dream images, despite studies that have retrospectively compared the direction of rapid eye movements to the dream recall recorded after having awakened the sleeper. We used the model of rapid eye movement sleep behaviour disorder (when patients enact their dreams by persistence of muscle tone) to determine directly whether the eyes move in the same directions as the head and limbs. In 56 patients with rapid eye movement sleep behaviour disorder and 17 healthy matched controls, the eye movements were monitored by electrooculography in four (right, left, up and down) directions, calibrated with a target and synchronized with video and sleep monitoring. The rapid eye movement sleep behaviour disorder-associated behaviours occurred 2.1 times more frequently during rapid eye movement sleep with than without rapid eye movements, and more often during or after rapid eye movements than before. Rapid eye movement density, index and complexity were similar in patients with rapid eye movement sleep behaviour disorder and controls. When rapid eye movements accompanied goal-oriented motor behaviour during rapid eye movement sleep behaviour disorder (e.g. grabbing a fictive object, hand greetings, climbing a ladder), which happened in 19 sequences, 82% were directed towards the action of the patient (same plane and direction). When restricted to the determinant rapid eye movements, the concordance increased to 90%. Rapid eye movements were absent in 38-42% of behaviours. This directional coherence between limbs, head and eye movements during rapid eye movement sleep behaviour disorder suggests that, when present, rapid eye movements imitate the scanning of the dream scene. Since the rapid eye movements are similar in subjects with and without rapid eye movement sleep behaviour disorder, this concordance can be extended

  10. Dynamics of Two-Dimensional Eye-Head Tracking.

    DTIC Science & Technology

    1981-06-15

    one without a visual feedback display. Each of these tracking methods involves eye-head coordination, but in different ways . Durin6 .e Summer of 1979...methods’involves eye-head coordination, but in different ways . During the Summer of 1979, experimental work was carried out at the tracking laboratory of the... different ways . For eye tracking itself (with fixed head position), several models have been pro- posed 11,12,13,14 ; however, they may serve, at best

  11. Lack of emergency hand surgery: discrepancy between elective and emergency hand care.

    PubMed

    Mueller, Melissa A; Zaydfudim, Victor; Sexton, Kevin W; Shack, R Bruce; Thayer, Wesley P

    2012-05-01

    Wrist, hand, and finger trauma are the most common injuries presenting to emergency departments. Shortage of emergency hand care is an emerging problem, as on-call hand coverage declines. This study evaluates the availability of elective and emergency hand surgery services in Tennessee, with the use of telephone surveys administered to emergency department and operating facility management. One hundred eleven Tennessee hospitals completed the surveys (93% response rate). In all, 77% of hospitals offer elective hand surgery, 58% offer basic emergency hand services, 18% offer occasional hand specialist call coverage and only 7% of hospitals have 24/7 hand specialist call coverage. Hospitals with hand specialists have significantly more payer charges from commercial insurance than hospitals without hand specialists (26.1% vs. 16.1%, P < 0.001). Our results strongly support the need for increased emergency hand coverage. Solutions include creating multihospital coordinated call schedules, increasing incentives for call coverage, and training more hand specialists.

  12. The role of action prediction and inhibitory control for joint action coordination in toddlers.

    PubMed

    Meyer, M; Bekkering, H; Haartsen, R; Stapel, J C; Hunnius, S

    2015-11-01

    From early in life, young children eagerly engage in social interactions. Yet, they still have difficulties in performing well-coordinated joint actions with others. Adult literature suggests that two processes are important for smooth joint action coordination: action prediction and inhibitory control. The aim of the current study was to disentangle the potential role of these processes in the early development of joint action coordination. Using a simple turn-taking game, we assessed 2½-year-old toddlers' joint action coordination, focusing on timing variability and turn-taking accuracy. In two additional tasks, we examined their action prediction capabilities with an eye-tracking paradigm and examined their inhibitory control capabilities with a classic executive functioning task (gift delay task). We found that individual differences in action prediction and inhibitory action control were distinctly related to the two aspects of joint action coordination. Toddlers who showed more precision in their action predictions were less variable in their action timing during the joint play. Furthermore, toddlers who showed more inhibitory control in an individual context were more accurate in their turn-taking performance during the joint action. On the other hand, no relation between timing variability and inhibitory control or between turn-taking accuracy and action prediction was found. The current results highlight the distinct role of action prediction and inhibitory action control for the quality of joint action coordination in toddlers. Underlying neurocognitive mechanisms and implications for processes involved in joint action coordination in general are discussed.

  13. Relation of eye dominance with performance and subjective ratings in golf putting.

    PubMed

    Sugiyama, Yoshio; Lee, Mi-Sook

    2005-06-01

    Previous research has discussed the interaction of hand preference, eye dominance, and sport performance. In this study, the relation of eye dominance with performance and subjective ratings in golf putting was investigated. 47 right-handed Japanese students from a college of physical education putted 10 balls to a drawn circle 3 m away, each under right-handed and left-handed stance conditions. Putting performance was measured by the number of successful putts. After putting in each condition, they rated subjective visibility and feelings of hitting. Analyses indicated that right-eyed subjects had significantly better performance using the right-handed stance than the left-handed stance, whereas left-eyed subjects showed the opposite. Most subjective ratings were more positive with right-handed stance for both right-eyed and left-eyed subjects. These findings suggest that eye dominance could have some influence on putting performance of Japanese novice golfers.

  14. Eye and orbit ultrasound

    MedlinePlus

    Echography - eye orbit; Ultrasound - eye orbit; Ocular ultrasonography; Orbital ultrasonography ... ophthalmology department of a hospital or clinic. Your eye is numbed with medicine (anesthetic drops). The ultrasound ...

  15. Eye Twitching

    MedlinePlus

    ... aspects of life. Hemifacial spasm involves twitches of muscles on one side of the face, including the eyelid. Eye twitching usually goes away on its own within a few days or weeks with rest, stress relief and decreased caffeine. Schedule an appointment with your doctor if: The ...

  16. Googly Eyes

    ERIC Educational Resources Information Center

    Boss, Susan

    2009-01-01

    Beverage take-out trays are funky in their form and function. In this article, the author describes how to make googly eye masks out of discarded take-out trays and other common recycled or discarded materials. (Contains 1 online resource.)

  17. Eye and head movements shape gaze shifts in Indian peafowl.

    PubMed

    Yorzinski, Jessica L; Patricelli, Gail L; Platt, Michael L; Land, Michael F

    2015-12-01

    Animals selectively direct their visual attention toward relevant aspects of their environments. They can shift their attention using a combination of eye, head and body movements. While we have a growing understanding of eye and head movements in mammals, we know little about these processes in birds. We therefore measured the eye and head movements of freely behaving Indian peafowl (Pavo cristatus) using a telemetric eye-tracker. Both eye and head movements contributed to gaze changes in peafowl. When gaze shifts were smaller, eye movements played a larger role than when gaze shifts were larger. The duration and velocity of eye and head movements were positively related to the size of the eye and head movements, respectively. In addition, the coordination of eye and head movements in peafowl differed from that in mammals; peafowl exhibited a near-absence of the vestibulo-ocular reflex, which may partly result from the peafowl's ability to move their heads as quickly as their eyes.

  18. Concurrent directional adaptation of reactive saccades and hand movements to target displacements of different size.

    PubMed

    Borisova, Steliana; Bock, Otmar; Grigorova, Valentina

    2014-01-01

    When eye and hand movements are concurrently aimed at double-step targets that call for equal and opposite changes of response direction (-10° for the eyes, +10° for the hand), adaptive recalibration of both motor systems is strongly attenuated; instead, hand but not eye movements are changed by corrective strategies (V. Grigorova et al., 2013a). The authors introduce a complementary paradigm, where double-step targets call for a -10° change of eye and a -30° change for hand movements. If compared to control subjects adapting only the eyes or only the hand, adaptive improvements were comparable for the eyes but were twice as large for the hand; in contrast, eye and hand aftereffects were comparable to those in control subjects. The authors concluded that concurrent exposure of eyes and hand to steps of the same direction but different size facilitated hand strategies, but didn't affect recalibration. This finding together with previous one (V. Grigorova et al., 2013a), suggests that concurrent adaptation of eyes and hand reveals different mechanisms of recalibration for step sign and step size, which are shared by reactive saccades and hand movements. However, hand mostly benefits from strategies provoked by the difference in target step sign and size.

  19. Poisson Coordinates.

    PubMed

    Li, Xian-Ying; Hu, Shi-Min

    2013-02-01

    Harmonic functions are the critical points of a Dirichlet energy functional, the linear projections of conformal maps. They play an important role in computer graphics, particularly for gradient-domain image processing and shape-preserving geometric computation. We propose Poisson coordinates, a novel transfinite interpolation scheme based on the Poisson integral formula, as a rapid way to estimate a harmonic function on a certain domain with desired boundary values. Poisson coordinates are an extension of the Mean Value coordinates (MVCs) which inherit their linear precision, smoothness, and kernel positivity. We give explicit formulas for Poisson coordinates in both continuous and 2D discrete forms. Superior to MVCs, Poisson coordinates are proved to be pseudoharmonic (i.e., they reproduce harmonic functions on n-dimensional balls). Our experimental results show that Poisson coordinates have lower Dirichlet energies than MVCs on a number of typical 2D domains (particularly convex domains). As well as presenting a formula, our approach provides useful insights for further studies on coordinates-based interpolation and fast estimation of harmonic functions.

  20. Association between eye dominance and training for rifle marksmanship: a pilot study.

    PubMed

    Jones, L F; Classe, J G; Hester, M; Harris, K

    1996-02-01

    This pilot study was performed to determine the effect, if any, exerted by crossed dominance (contralateral hand and eye dominance) on the ability of novice riflemen to learn how to accurately shoot a rifle. Sighting dominance was used to determine the dominant eye. Hand dominance was determined by the arm used to shoulder the rifle in the shooting position. Subjects were 308 military recruits at the Fort Benning Army Base in Columbus, Georgia, who had undergone basic training in rifle marksmanship. Qualification scores obtained at the base rifle range were used to measure the subjects' ability to learn marksmanship skills. The subjects with right-hand/right-eye and left-hand/left-eye (uncrossed) dominance had qualification scores that were significantly higher (p = .009) than the subjects with right hand/left-eye and left-hand/right-eye (crossed) dominance. A significantly higher percentage of subjects with uncrossed dominance achieved rifle qualification (86.1 percent) than subjects with crossed dominance (56.5 percent) (p = .000). The learning of rifle marksmanship is influenced by eye dominance. Individuals who shoot right handed and are left-eye dominant or who shoot left handed and are right-eye dominant do not learn marksmanship skills as readily as individuals who have matched eye and hand dominance. Since crossed hand and eye dominance can be easily determined, it should be possible to identify cross dominant individuals and provide them with special training so that they can perform at a higher level of skill.

  1. Eye Complications in IBD

    MedlinePlus

    ... Home > Resources > Eye Complications in IBD Go Back Eye Complications in IBD Email Print + Share Approximately 10% ... doctor’s attention sooner rather than later. TYPES OF EYE DISORDERS UVEITIS One of the most common eye ...

  2. Eye Injuries at Work

    MedlinePlus

    ... Ophthalmologist Patient Stories Español Eye Health / Tips & Prevention Eye Injuries Sections Preventing Eye Injuries Recognizing and Treating ... Numbers — Infographic Five Steps to Safer Champagne Celebrations Eye Injuries at Work Edited by: Shirley Dang Feb. ...

  3. Conjunctivitis (Pink Eye)

    MedlinePlus

    ... can be embedded on web pages. Conjunctivitis (Pink Eye) One-Page Overview Pink, itchy eyes? Conjunctivitis – or ... yourself from getting and spreading pink eye . Pink Eye: What To Do Discusses causes and treatment, when ...

  4. Eye Injuries at Home

    MedlinePlus

    ... Ophthalmologist Patient Stories Español Eye Health / Tips & Prevention Eye Injuries Sections Preventing Eye Injuries Recognizing and Treating ... Numbers — Infographic Five Steps to Safer Champagne Celebrations Eye Injuries at Home Reviewed by: Brenda Pagan-Duran ...

  5. Eye muscle repair - discharge

    MedlinePlus

    ... Lazy eye repair - discharge; Strabismus repair - discharge; Extraocular muscle surgery - discharge ... You or your child had eye muscle repair surgery to correct eye muscle ... term for crossed eyes is strabismus. Children most often ...

  6. Why Do Eyes Water?

    MedlinePlus

    ... Happens in the Operating Room? Why Do Eyes Water? KidsHealth > For Kids > Why Do Eyes Water? A ... out of your nose. continue Why Do Eyes Water? Eyes water for lots of different reasons besides ...

  7. Why Do Eyes Water?

    MedlinePlus

    ... Lifesaver Kids Talk About: Coaches Why Do Eyes Water? KidsHealth > For Kids > Why Do Eyes Water? Print ... out of your nose. continue Why Do Eyes Water? Eyes water for lots of different reasons besides ...

  8. Eye Movement Disorders

    MedlinePlus

    ... t work properly. There are many kinds of eye movement disorders. Two common ones are Strabismus - a disorder ... of the eyes, sometimes called "dancing eyes" Some eye movement disorders are present at birth. Others develop over ...

  9. Degradation of Binocular Coordination during Sleep Deprivation

    PubMed Central

    Tong, Jianliang; Maruta, Jun; Heaton, Kristin J.; Maule, Alexis L.; Rajashekar, Umesh; Spielman, Lisa A.; Ghajar, Jamshid

    2016-01-01

    To aid a clear and unified visual perception while tracking a moving target, both eyes must be coordinated, so the image of the target falls on approximately corresponding areas of the fovea of each eye. The movements of the two eyes are decoupled during sleep, suggesting a role of arousal in regulating binocular coordination. While the absence of visual input during sleep may also contribute to binocular decoupling, sleepiness is a state of reduced arousal that still allows for visual input, providing a context within which the role of arousal in binocular coordination can be studied. We examined the effects of sleep deprivation on binocular coordination using a test paradigm that we previously showed to be sensitive to sleep deprivation. We quantified binocular coordination with the SD of the distance between left and right gaze positions on the screen. We also quantified the stability of conjugate gaze on the target, i.e., gaze–target synchronization, with the SD of the distance between the binocular average gaze and the target. Sleep deprivation degraded the stability of both binocular coordination and gaze–target synchronization, but between these two forms of gaze control the horizontal and vertical components were affected differently, suggesting that disconjugate and conjugate eye movements are under different regulation of attentional arousal. The prominent association found between sleep deprivation and degradation of binocular coordination in the horizontal direction may be used for a fit-for-duty assessment. PMID:27379009

  10. Eye contricks

    PubMed Central

    Wade, Nicholas J

    2011-01-01

    Pictorial images are icons as well as eye-cons: they provide distillations of objects or ideas into simpler shapes. They create the impression of representing that which cannot be presented. Even at the level of the photograph, the links between icon and object are tenuous. The dimensions of depth and motion are missing from icons, and these alone introduce all manner of potential ambiguities. The history of art can be considered as exploring the missing link between icon and object. Eye-cons can also be illusions—tricks of vision so that what is seen does not necessarily correspond to what is physically presented. Pictorial images can be spatialised or stylised; spatialised images generally share some of the projective characteristics of the object represented. Written words are also icons, but they do not resemble the objects they represent—they are stylised or conventional. Icons as stylised words and spatialised images were set in delightful opposition by René Magritte in a series of pipe paintings, and this theme is here alluded to. Most of visual science is now concerned with icons—two-dimensional displays on computer monitors. Is vision now the science of eye-cons? PMID:23145240

  11. Integrated and Independent Learning of Hand-Related Constituent Sequences

    ERIC Educational Resources Information Center

    Berner, Michael P.; Hoffmann, Joachim

    2009-01-01

    In almost all daily activities fingers of both hands are used in coordinated succession. The present experiments explored whether learning in such tasks pertains not only to the overall sequence spanning both hands but also to the constituent sequences of each hand. In a serial reaction time task, 2 repeating hand-related sequences were…

  12. Integrated and Independent Learning of Hand-Related Constituent Sequences

    ERIC Educational Resources Information Center

    Berner, Michael P.; Hoffmann, Joachim

    2009-01-01

    In almost all daily activities fingers of both hands are used in coordinated succession. The present experiments explored whether learning in such tasks pertains not only to the overall sequence spanning both hands but also to the constituent sequences of each hand. In a serial reaction time task, 2 repeating hand-related sequences were…

  13. Black Eye: First Aid

    MedlinePlus

    First aid Black eye: First aid Black eye: First aid By Mayo Clinic Staff A black eye is caused by bleeding under the skin around the eye. Most injuries that cause a black eye aren't serious. But a black eye ...

  14. Eye movement detector calibration device.

    PubMed

    Pruchsner, William R; Zenker, Michael; Enderle, John D

    2004-01-01

    Presented is a device developed for specifically calibrating and validating the operation of Eye Movement Detectors or Monitors. The Calibrator centers on two one inch diameter HPDE spheres representing the eyes. A Laser Module is embedded in the rear of each sphere emitting a beam against a target divided in equal measurement intervals mounted as part of the device. The device moves the "eyes" about its center axes enabling the user to validate any vertical, horizontal, or X-Y combination eye position in a plus or minus fifteen degree range. Although hand controlled, the Calibrator can be motorized with stepper motors or other desired drivers. Anatomically correct sized pupils are imbedded in the front of each "eye," thereby acting as the target for whichever system is under test by the very portable Calibrator. Currently, a simple battery controlled circuit controls the laser modules and other electric requirements with accommodation for additional circuit components if required in the future. Specifically designed for validating the operation of an IR Reflective Differencing Saccadic Eye Movement Measurement System, the Calibrator can also be used with little or no alteration for validation of camera systems and other types of devices.

  15. Tracking with the mind's eye

    NASA Technical Reports Server (NTRS)

    Krauzlis, R. J.; Stone, L. S.

    1999-01-01

    The two components of voluntary tracking eye-movements in primates, pursuit and saccades, are generally viewed as relatively independent oculomotor subsystems that move the eyes in different ways using independent visual information. Although saccades have long been known to be guided by visual processes related to perception and cognition, only recently have psychophysical and physiological studies provided compelling evidence that pursuit is also guided by such higher-order visual processes, rather than by the raw retinal stimulus. Pursuit and saccades also do not appear to be entirely independent anatomical systems, but involve overlapping neural mechanisms that might be important for coordinating these two types of eye movement during the tracking of a selected visual object. Given that the recovery of objects from real-world images is inherently ambiguous, guiding both pursuit and saccades with perception could represent an explicit strategy for ensuring that these two motor actions are driven by a single visual interpretation.

  16. Tracking with the mind's eye

    NASA Technical Reports Server (NTRS)

    Krauzlis, R. J.; Stone, L. S.

    1999-01-01

    The two components of voluntary tracking eye-movements in primates, pursuit and saccades, are generally viewed as relatively independent oculomotor subsystems that move the eyes in different ways using independent visual information. Although saccades have long been known to be guided by visual processes related to perception and cognition, only recently have psychophysical and physiological studies provided compelling evidence that pursuit is also guided by such higher-order visual processes, rather than by the raw retinal stimulus. Pursuit and saccades also do not appear to be entirely independent anatomical systems, but involve overlapping neural mechanisms that might be important for coordinating these two types of eye movement during the tracking of a selected visual object. Given that the recovery of objects from real-world images is inherently ambiguous, guiding both pursuit and saccades with perception could represent an explicit strategy for ensuring that these two motor actions are driven by a single visual interpretation.

  17. A new neural net approach to robot 3D perception and visuo-motor coordination

    NASA Technical Reports Server (NTRS)

    Lee, Sukhan

    1992-01-01

    A novel neural network approach to robot hand-eye coordination is presented. The approach provides a true sense of visual error servoing, redundant arm configuration control for collision avoidance, and invariant visuo-motor learning under gazing control. A 3-D perception network is introduced to represent the robot internal 3-D metric space in which visual error servoing and arm configuration control are performed. The arm kinematic network performs the bidirectional association between 3-D space arm configurations and joint angles, and enforces the legitimate arm configurations. The arm kinematic net is structured by a radial-based competitive and cooperative network with hierarchical self-organizing learning. The main goal of the present work is to demonstrate that the neural net representation of the robot 3-D perception net serves as an important intermediate functional block connecting robot eyes and arms.

  18. A new neural net approach to robot 3D perception and visuo-motor coordination

    NASA Technical Reports Server (NTRS)

    Lee, Sukhan

    1992-01-01

    A novel neural network approach to robot hand-eye coordination is presented. The approach provides a true sense of visual error servoing, redundant arm configuration control for collision avoidance, and invariant visuo-motor learning under gazing control. A 3-D perception network is introduced to represent the robot internal 3-D metric space in which visual error servoing and arm configuration control are performed. The arm kinematic network performs the bidirectional association between 3-D space arm configurations and joint angles, and enforces the legitimate arm configurations. The arm kinematic net is structured by a radial-based competitive and cooperative network with hierarchical self-organizing learning. The main goal of the present work is to demonstrate that the neural net representation of the robot 3-D perception net serves as an important intermediate functional block connecting robot eyes and arms.

  19. Deficits of Visuospatial Attention with Reflexive Orienting Induced by Eye-Gazed Cues in Children with Developmental Coordination Disorder in the Lower Extremities: An Event-Related Potential Study

    ERIC Educational Resources Information Center

    Tsai, Chia-Liang; Pan, Chien-Yu; Chang, Yu-Kai; Wang, Chun-Hao; Tseng, Ko-Da

    2010-01-01

    The present study aims to investigate and compare the behavioral performance and event-related potentials (ERPs) measures in children with developmental coordination disorder (DCD) and typically developing (TD) children when performing the visuospatial attention task with reflexive orienting. Thirty children with DCD and 30 TD children were…

  20. Novel automatic eye detection and tracking algorithm

    NASA Astrophysics Data System (ADS)

    Ghazali, Kamarul Hawari; Jadin, Mohd Shawal; Jie, Ma; Xiao, Rui

    2015-04-01

    The eye is not only one of the most complex but also the most important sensory organ of the human body. Eye detection and eye tracking are basement and hot issue in image processing. A non-invasive eye location and eye tracking is promising for hands-off gaze-based human-computer interface, fatigue detection, instrument control by paraplegic patients and so on. For this purpose, an innovation work frame is proposed to detect and tracking eye in video sequence in this paper. The contributions of this work can be divided into two parts. The first contribution is that eye filters were trained which can detect eye location efficiently and accurately without constraints on the background and skin colour. The second contribution is that a framework of tracker based on sparse representation and LK optic tracker were built which can track eye without constraint on eye status. The experimental results demonstrate the accuracy aspects and the real-time applicability of the proposed approach.

  1. Hand Grasping Synergies As Biometrics

    PubMed Central

    Patel, Vrajeshri; Thukral, Poojita; Burns, Martin K.; Florescu, Ionut; Chandramouli, Rajarathnam; Vinjamuri, Ramana

    2017-01-01

    Recently, the need for more secure identity verification systems has driven researchers to explore other sources of biometrics. This includes iris patterns, palm print, hand geometry, facial recognition, and movement patterns (hand motion, gait, and eye movements). Identity verification systems may benefit from the complexity of human movement that integrates multiple levels of control (neural, muscular, and kinematic). Using principal component analysis, we extracted spatiotemporal hand synergies (movement synergies) from an object grasping dataset to explore their use as a potential biometric. These movement synergies are in the form of joint angular velocity profiles of 10 joints. We explored the effect of joint type, digit, number of objects, and grasp type. In its best configuration, movement synergies achieved an equal error rate of 8.19%. While movement synergies can be integrated into an identity verification system with motion capture ability, we also explored a camera-ready version of hand synergies—postural synergies. In this proof of concept system, postural synergies performed well, but only when specific postures were chosen. Based on these results, hand synergies show promise as a potential biometric that can be combined with other hand-based biometrics for improved security. PMID:28512630

  2. Hand Grasping Synergies As Biometrics.

    PubMed

    Patel, Vrajeshri; Thukral, Poojita; Burns, Martin K; Florescu, Ionut; Chandramouli, Rajarathnam; Vinjamuri, Ramana

    2017-01-01

    Recently, the need for more secure identity verification systems has driven researchers to explore other sources of biometrics. This includes iris patterns, palm print, hand geometry, facial recognition, and movement patterns (hand motion, gait, and eye movements). Identity verification systems may benefit from the complexity of human movement that integrates multiple levels of control (neural, muscular, and kinematic). Using principal component analysis, we extracted spatiotemporal hand synergies (movement synergies) from an object grasping dataset to explore their use as a potential biometric. These movement synergies are in the form of joint angular velocity profiles of 10 joints. We explored the effect of joint type, digit, number of objects, and grasp type. In its best configuration, movement synergies achieved an equal error rate of 8.19%. While movement synergies can be integrated into an identity verification system with motion capture ability, we also explored a camera-ready version of hand synergies-postural synergies. In this proof of concept system, postural synergies performed well, but only when specific postures were chosen. Based on these results, hand synergies show promise as a potential biometric that can be combined with other hand-based biometrics for improved security.

  3. Motor coordination uses external spatial coordinates independent of developmental vision.

    PubMed

    Heed, Tobias; Röder, Brigitte

    2014-07-01

    The constraints that guide bimanual movement coordination are informative about the processing principles underlying movement planning in humans. For example, symmetry relative to the body midline benefits finger and hand movements independent of hand posture. This symmetry constraint has been interpreted to indicate that movement coordination is guided by a perceptual code. Although it has been assumed implicitly that the perceptual system at the heart of this constraint is vision, this relationship has not been tested. Here, congenitally blind and sighted participants made symmetrical and non-symmetrical (that is, parallel) bimanual tapping and finger oscillation movements. For both groups, symmetrical movements were executed more correctly than parallel movements, independent of anatomical constraints like finger homology and hand posture. For the blind, the reliance on external spatial factors in movement coordination stands in stark contrast to their use of an anatomical reference frame in perceptual processing. Thus, the externally coded symmetry constraint evident in bimanual coordination can develop in the absence of the visual system, suggesting that the visual system is not critical for the establishment of an external-spatial reference frame in movement coordination. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Multiple Sensory-Motor Pathways Lead to Coordinated Visual Attention.

    PubMed

    Yu, Chen; Smith, Linda B

    2017-02-01

    Joint attention has been extensively studied in the developmental literature because of overwhelming evidence that the ability to socially coordinate visual attention to an object is essential to healthy developmental outcomes, including language learning. The goal of this study was to understand the complex system of sensory-motor behaviors that may underlie the establishment of joint attention between parents and toddlers. In an experimental task, parents and toddlers played together with multiple toys. We objectively measured joint attention-and the sensory-motor behaviors that underlie it-using a dual head-mounted eye-tracking system and frame-by-frame coding of manual actions. By tracking the momentary visual fixations and hand actions of each participant, we precisely determined just how often they fixated on the same object at the same time, the visual behaviors that preceded joint attention and manual behaviors that preceded and co-occurred with joint attention. We found that multiple sequential sensory-motor patterns lead to joint attention. In addition, there are developmental changes in this multi-pathway system evidenced as variations in strength among multiple routes. We propose that coordinated visual attention between parents and toddlers is primarily a sensory-motor behavior. Skill in achieving coordinated visual attention in social settings-like skills in other sensory-motor domains-emerges from multiple pathways to the same functional end.

  5. Impact of Virtual Environments on Sensorimotor Coordination and User Safety

    NASA Technical Reports Server (NTRS)

    Harm, Deborah L.; Taylor, Laura C.; Kennedy, Robert S.; Reschke, Millard F.

    2011-01-01

    One critical unresolved issue related to the safe use of virtual environments (VEs) is maladaptive sensorimotor coordination following exposure to VEs. Moving visual displays used in VEs, especially in the absence of concordant vestibular signals leads to adaptive responses during VE exposure, but maladaptive responses following return to the normal environment. In the current set of investigations, we examined the effect of HMD and dome VE displays on eye-head-hand coordination, gaze holding and postural equilibrium. Subjects (61) performed a navigation and a pick and place task. Further, we compared 30 min and 60 min exposures across 3 days (each separated by 1 day). A subset of these results will be presented. In general, we found significant decrements in all three measures following exposure to the VEs. In addition, we found that these disturbances generally recovered within 1-2 hrs and decreased across days. These findings suggest the need for post-VE monitoring of sensorimotor coordination and for developing a set of recommendations for users concerning activities that are safe to engage in following use of a VE.

  6. COORDINATED AV.

    ERIC Educational Resources Information Center

    CLEAVES, PAUL C.; AND OTHERS

    THE INSTRUCTIONAL MATERIALS CENTER IS LOCATED IN THE LOCAL HIGH SCHOOL AND SUPPLIES ALL SCHOOLS IN THE AREA. AUDIOVISUAL EQUIPMENT ORDERS, AFTER SELECTIONS ARE MADE BY THE CLASSROOM TEACHER, ARE PROCESSED BY THE CENTER, CONFIRMED AND DELIVERED BY TRUCK THREE TIMES EACH WEEK. EACH SCHOOL HAS A BUILDING COORDINATOR WHO CHECKS THE ORDERS INTO THE…

  7. COORDINATED AV.

    ERIC Educational Resources Information Center

    CLEAVES, PAUL C.; AND OTHERS

    THE INSTRUCTIONAL MATERIALS CENTER IS LOCATED IN THE LOCAL HIGH SCHOOL AND SUPPLIES ALL SCHOOLS IN THE AREA. AUDIOVISUAL EQUIPMENT ORDERS, AFTER SELECTIONS ARE MADE BY THE CLASSROOM TEACHER, ARE PROCESSED BY THE CENTER, CONFIRMED AND DELIVERED BY TRUCK THREE TIMES EACH WEEK. EACH SCHOOL HAS A BUILDING COORDINATOR WHO CHECKS THE ORDERS INTO THE…

  8. The visual development of hand-centered receptive fields in a neural network model of the primate visual system trained with experimentally recorded human gaze changes.

    PubMed

    Galeazzi, Juan M; Navajas, Joaquín; Mender, Bedeho M W; Quian Quiroga, Rodrigo; Minini, Loredana; Stringer, Simon M

    2016-01-01

    Neurons have been found in the primate brain that respond to objects in specific locations in hand-centered coordinates. A key theoretical challenge is to explain how such hand-centered neuronal responses may develop through visual experience. In this paper we show how hand-centered visual receptive fields can develop using an artificial neural network model, VisNet, of the primate visual system when driven by gaze changes recorded from human test subjects as they completed a jigsaw. A camera mounted on the head captured images of the hand and jigsaw, while eye movements were recorded using an eye-tracking device. This combination of data allowed us to reconstruct the retinal images seen as humans undertook the jigsaw task. These retinal images were then fed into the neural network model during self-organization of its synaptic connectivity using a biologically plausible trace learning rule. A trace learning mechanism encourages neurons in the model to learn to respond to input images that tend to occur in close temporal proximity. In the data recorded from human subjects, we found that the participant's gaze often shifted through a sequence of locations around a fixed spatial configuration of the hand and one of the jigsaw pieces. In this case, trace learning should bind these retinal images together onto the same subset of output neurons. The simulation results consequently confirmed that some cells learned to respond selectively to the hand and a jigsaw piece in a fixed spatial configuration across different retinal views.

  9. Tropical diabetic hand syndrome: a case report.

    PubMed

    Yeika, Eugene Vernyuy; Tchoumi Tantchou, Jacques Cabral; Foryoung, Joyce Bei; Tolefac, Paul Nkemtendong; Efie, Derrick Tembi; Choukem, Siméon Pierre

    2017-02-13

    Tropical diabetic hand syndrome describes a complex hand sepsis affecting patients with diabetes across the tropics and often results from a trivial hand trauma. The clinical presentation of this syndrome is variable and ranges from localised swelling and cellulitis, with or without ulceration of the hand to progressive fulminant hand sepsis, and gangrene affecting the entire limb which may be fatal. Tropical diabetic hand syndrome could lead to permanent disability and death as a result of delay in presentation, late diagnosis and late medical and surgical intervention. This indexed case acts as an eye opener for physicians to the existence of this hand sepsis. We report the case of a 57 year-old black African female diabetic who was referred to our centre for the management of a suppurating ulcer and swelling of the left hand of two weeks duration. On examination and work-up, the patient was found to have Lawal Group III left diabetic hand syndrome and was managed with parenteral antibiotics, radical debridement and the hand was eventually amputated. She died 7 days following amputation from overwhelming sepsis. Though tropical diabetic hand syndrome is a relatively rare complication of diabetes, it can be fatal as in this case report. Early diagnosis and proper management would yield better outcome. Initial management should include aggressive intravenous broad-spectrum antibiotics with anaerobic coverage. Classification of tropical diabetic hand syndrome will assist physicians and surgeons in decision making, proper management and easy communication.

  10. Billie's eyes.

    PubMed

    Dunning, S E

    1993-03-01

    The author, a nurse, is personally opposed to abortion; however, her earlier encounter with a victim of an illegal abortion has prevented her from joining campaigns to reinstate bans on abortion rights. The woman, "Billie," presented to an inner-city Chicago hospital in 1970 with hemorrhaging. She had delayed going for treatment because she feared being imprisoned for having obtained an abortion. She rapidly entered septic shock, with hypotension, confusion, and hallucinations. Physicians removed her infected uterus and ovaries. Subsequent kidney failure necessitated the transfer of this young woman to another hospital where she could receive dialysis. The author was unable to obtain follow-up information on whether Billie survived. She remains haunted by the memory of Billie's wide, frightened eyes as she was placed in the ambulance. It is this memory, and the knowledge that desperate women like Billie will find someone, somewhere to perform an illegal abortion, that is behind the author's reluctant support for the right to choose.

  11. Design of a computer game using an eye-tracking device for eye's activity rehabilitation

    NASA Astrophysics Data System (ADS)

    Lin, Chern-Sheng; Huan, Chia-Chin; Chan, Chao-Ning; Yeh, Mau-Shiun; Chiu, Chuang-Chien

    2004-07-01

    An eye mouse interface that can be used to operate a computer using the movement of the eyes is described. We developed this eye-tracking system for eye motion disability rehabilitation. When the user watches the screen of a computer, a charge-coupled device will catch images of the user's eye and transmit it to the computer. A program, based on a new cross-line tracking and stabilizing algorithm, will locate the center point of the pupil in the images. The calibration factors and energy factors are designed for coordinate mapping and blink functions. After the system transfers the coordinates of pupil center in the images to the display coordinate, it will determine the point at which the user gazed on the display, then transfer that location to the game subroutine program. We used this eye-tracking system as a joystick to play a game with an application program in a multimedia environment. The experimental results verify the feasibility and validity of this eye-game system and the rehabilitation effects for the user's visual movement.

  12. Diabetes - eye care

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000078.htm Diabetes - eye care To use the sharing features on this ... prevent them from getting worse. You Need Regular eye Exams Every year, you should have an eye ...

  13. Eye muscle repair - slideshow

    MedlinePlus

    ... page: //medlineplus.gov/ency/presentations/100062.htm Eye muscle repair - series—Normal anatomy To use the sharing ... the eyeball to the eye socket. The external muscles of the eye are found behind the conjunctiva. ...

  14. Eye Cosmetic Safety

    MedlinePlus

    ... when they are new. FDA has an Import Alert in effect for cosmetics -- including eye cosmetics -- contaminated ... in the area of the eye. An import alert for cosmetics containing illegal colors lists several eye ...

  15. Dilating Eye Drops

    MedlinePlus

    ... sometimes used to treat eye diseases, such as amblyopia and inflammation. How long do dilating drops last? ... used to treat certain eye diseases, such as amblyopia and inflammation in the eye. These therapeutic dilating ...

  16. Acute Arterial Thrombosis of the Hand.

    PubMed

    Iannuzzi, Nicholas P; Higgins, James P

    2015-10-01

    Arterial thrombosis of the hand occurs infrequently but may result in considerable morbidity and compromise of hand function. The hand surgeon may be called upon to direct management in cases of acute arterial thrombosis of the hand and should have an understanding of the available diagnostic tools and treatment modalities. This article discusses the vascular anatomy of the hand and clinical manifestations of arterial thrombosis. Differences between isolated thrombosis and diffuse intravascular injury are detailed, and treatment options for these conditions are described. Appropriate care often requires coordination with interventional radiologists or vascular surgeons. Outcomes after treatment of arterial thrombosis of the hand are variable, and prognosis may be related to whether isolated thrombosis or diffuse intravascular injury is present. Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  17. Control design and implementation of a novel master-slave surgery robot system, MicroHand A.

    PubMed

    Sang, Hongqiang; Wang, Shuxin; Li, Jianmin; He, Chao; Zhang, Lin'an; Wang, Xiaofei

    2011-09-01

    Compared with conventional minimally invasive surgery and open surgery, robotic-assisted minimally invasive surgery can overcome or eliminate drawbacks caused by operator restrictions, motion limitation by the trocar and the image system, such as fatigue, trembling, low precision, constrained degree-of-freedom, poor hand-eye coordination and restricted surgical vision. In this paper, a novel partly tendon-driven master-slave robot system is proposed to assist minimally invasive surgery and a master-slave control architecture is developed for abdominal surgical operations. A novel master-slave surgery robot system named MicroHand A has been developed. A kinematic analysis of master and slave manipulators was conducted, based on screw theory and vector loop equation. The relationships of the tendon-driven multi-DOF surgical instrument among Cartesian space, actuator space and joint space were derived for control purposes. The control system architecture of the MicroHand A was designed with intuitive motion control and motion scaling control. Llewellyn's absolute stability criterion and the transparency of the one-DOF master-slave system are also analysed. Intuitive motion control under dissimilar kinematics in master-slave manipulations and motion scaling control were accomplished to solve absonant hand-eye coordination, kinematic dissimilarity and workspace mismatch of master-slave manipulator problems. A series of tests and animal experiments were carried out to evaluate system performance. The experimental results demonstrate that the system could accomplish intuitive motion control and motion scaling control, and that the control system is stable and reliable. The experiments performed on the MicroHand A robotic system yielded expected control results. The system satisfies the requirements of minimally invasive surgery. Intuitive motion control and motion scaling control under different kinematics for the master and slave have been implemented. Copyright © 2011

  18. Eyeing Ganymede

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Jupiter casts a baleful eye toward the moon Ganymede in this enhanced-contrast image from NASA's Cassini spacecraft.

    Jupiter's 'eye', the Great Red Spot, was captured just before disappearing around the eastern edge of the planet. The furrowed eyebrow above and to the left of the spot is a turbulent wake region caused by westward flow that has been deflected to the north and around the Red Spot. The smallest features visible are about 240 kilometers (150 miles) across.

    Within the band south of the Red Spot are a trio of white ovals, high pressure counterclockwise-rotating regions that are dynamically similar to the Red Spot. The dark filamentary features interspersed between white ovals are probably cyclonic circulations and, unlike the ovals, are rotating clockwise.

    Jupiter's equatorial zone stretching across the planet north of the Spot appears bright white, with gigantic plume clouds spreading out from the equator both to the northeast and to the southeast in a chevron pattern. This zone looks distinctly different than it did during the Voyager flyby 21 years ago. Then, its color was predominantly brown and the only white plumes conspicuous against the darker material beneath them were oriented southwest-to-northeast.

    Ganymede is Jupiter's largest moon, about 50 percent larger than our own Moon and larger than the planet Mercury. The visible details in this image are different geological terrains. Dark areas tend to be older and heavily cratered; brighter areas are younger and less cratered. Cassini images of Ganymede and Jupiter's other large moons taken near closest approach on Dec. 30 will have resolutions about four times better than that seen here.

    This image is a color composite of ones taken with different filters by Cassini's narrow-angle camera on Nov. 18, 2000, processed to enhance contrast. Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of

  19. Waiting for a hand: saccadic reaction time increases in proportion to hand reaction time when reaching under a visuomotor reversal

    PubMed Central

    Armstrong, Irene T.; Judson, Melissa; Munoz, Douglas P.; Johansson, Roland S.; Flanagan, J. Randall

    2013-01-01

    Although eye movement onset typically precedes hand movement onset when reaching to targets presented in peripheral vision, arm motor commands appear to be issued at around the same time, and possibly in advance, of eye motor commands. A fundamental question, therefore, is whether eye movement initiation is linked or yoked to hand movement. We addressed this issue by having participants reach to targets after adapting to a visuomotor reversal (or 180° rotation) between the position of the unseen hand and the position of a cursor controlled by the hand. We asked whether this reversal, which we expected to increase hand reaction time (HRT), would also increase saccadic reaction time (SRT). As predicted, when moving the cursor to targets under the reversal, HRT increased in all participants. SRT also increased in all but one participant, even though the task for the eyes—shifting gaze to the target—was unaltered by the reversal of hand position feedback. Moreover, the effects of the reversal on SRT and HRT were positively correlated across participants; those who exhibited the greatest increases in HRT also showed the greatest increases in SRT. These results indicate that the mechanisms underlying the initiation of eye and hand movements are linked. In particular, the results suggest that the initiation of an eye movement to a manual target depends, at least in part, on the specification of hand movement. PMID:23847494

  20. Eye movements of flatfish for the changes of gravity (II).

    PubMed

    Iwata, Kaori; Takabayashi, Akira; Miyachi, Ei-ichi

    2007-07-01

    In this study, we analysed the eye movements of flatfish for body tilting and compared with that of goldfish. The fish was fixed on the tilting table controlled by computer. The eye movements for body tilting along the different body axis were video-recorded. The vertical and torsional eye rotations were analysed frame by frame. In normal flatfish, vertical eye movement of left eye to leftward tilting was larger than that to rightward tilting. For head up or head down tilting, clear vertical eye movements were observed. On the other hand, torsional eye movements showed similar characteristics as goldfish. These results suggested that sacculus and lagena were important for otolith-ocular eye movements in flatfish.

  1. Satellite Coordination

    NASA Astrophysics Data System (ADS)

    Cohen, R. J.

    2004-06-01

    The Radio Regulations set out complex procedures to ensure that when new systems start to use the frequency bands allocated to them there is minimal disruption to existing systems using the same bands. The process of satellite coordination is described, and the issues for radio astronomy are discussed. In order to be protected by the ITU-R machinery radio telescopes need to be officially registered. The issue of paper satellites highlights the need for early registration to gain priority over incoming systems. Modern developments including the use of complex Monte-Carlo simulations to predict interference levels, and the issue of adjacent band interference, are discussed.

  2. Pathways to clean hands: highlights of successful hand hygiene implementation strategies in Europe.

    PubMed

    Magiorakos, A P; Leens, E; Drouvot, V; May-Michelangeli, L; Reichardt, C; Gastmeier, P; Wilson, K; Tannahill, M; McFarlane, E; Simon, A

    2010-05-06

    Hand hygiene is the most effective way to stop the spread of microorganisms and to prevent healthcare-associated infections (HAI). The World Health Organization launched the First Global Patient Safety Challenge - Clean Care is Safer Care - in 2005 with the goal to prevent HAI globally. This year, on 5 May, the WHO s initiative SAVE LIVES: Clean Your Hands, which focuses on increasing awareness of and improving compliance with hand hygiene practices, celebrated its second global day. In this article, four Member States of the European Union describe strategies that were implemented as part of their national hand hygiene campaigns and were found to be noteworthy. The strategies were: governmental support, the use of indicators for hand hygiene benchmarking, developing national surveillance systems for auditing alcohol-based hand rub consumption, ensuring seamless coordination of processes between health regions in countries with regionalised healthcare systems, implementing the WHO's My Five Moments for Hand Hygiene, and auditing of hand hygiene compliance.

  3. Improving eye care in Rwanda

    PubMed Central

    Scott, Kirstin; Rosewall, Thomas; Mackenzie, Graeme; Rehnborg, Gweneth; Hannema, Sjoerd; Presente, Max; Noe, Piet; Mathenge, Wanjiku; Nkurikiye, John; Habiyaremye, Francois; Dushime, Theophile

    2015-01-01

    Abstract Problem Visual impairment affects nearly 285 million people worldwide. Although there has been much progress in combating the burden of visual impairment through initiatives such as VISION 2020, barriers to progress, especially in African countries, remain high. Approach The Rwandan Ministry of Health has formed partnerships with several nongovernmental organizations and has worked to integrate their efforts to prevent and treat visual impairment, including presbyopia. Local setting Rwanda, an eastern African country of approximately 11 million people. Relevant changes The Rwandan Ministry of Health developed a single national plan that allows key partners in vision care to coordinate more effectively in measuring eye disease, developing eye care infrastructure, building capacity, controlling disease, and delivering and evaluating services. Lessons learnt Collaboration between stakeholders under a single national plan has ensured that resources and efforts are complementary, optimizing the ability to provide eye care. Improved access to primary eye care and insurance coverage has increased demand for services at secondary and tertiary levels. A comprehensive strategy that includes prevention as well as a supply chain for glasses and lenses is needed. PMID:26240465

  4. Eating for Your Eyes

    ERIC Educational Resources Information Center

    Stastny, Sherri Nordstrom; Garden-Robinson, Julie

    2011-01-01

    An educational program targeting older adults was developed to increase knowledge regarding nutrition and eye health. With age, the chance for eye disease increases, so prevention is critical. The Eating for Your Eyes program has promoted behavior changes regarding eye health among the participants. This program is easily replicated and use is…

  5. Eating for Your Eyes

    ERIC Educational Resources Information Center

    Stastny, Sherri Nordstrom; Garden-Robinson, Julie

    2011-01-01

    An educational program targeting older adults was developed to increase knowledge regarding nutrition and eye health. With age, the chance for eye disease increases, so prevention is critical. The Eating for Your Eyes program has promoted behavior changes regarding eye health among the participants. This program is easily replicated and use is…

  6. Eye Injuries (For Parents)

    MedlinePlus

    ... the eye nausea or vomiting after an eye injury Think Prevention! Kids who play sports should wear protective goggles or unbreakable glasses as needed. Keep chemicals and other potentially dangerous objects out of the reach of children. Reviewed by: Steven Dowshen, ... (Conjunctivitis) Eyes Corneal Abrasions Styes Activity: Eyes ...

  7. Eye Injuries in Sports

    MedlinePlus

    ... and Fitness Sports Safety Eye Injuries in Sports Eye Injuries in Sports Exercise and FitnessPrevention and WellnessSports Safety Share Eye Injuries ... injury, detached retina, patient education, patient information, penetrating eye ... Exercise and Fitness, Prevention and Wellness, Sports Safety June ...

  8. Update on hand hygiene.

    PubMed

    Boyce, John M

    2013-05-01

    Recent developments related to hand hygiene include new test methods for evaluating hand hygiene products, improvements in alcohol-based hand rubs, novel methods of hand antisepsis, and new strategies and technologies for monitoring hand hygiene practices among health care personnel.

  9. Multilevel coordination stability: Integrated goal representations in simultaneous intra-personal and inter-agent coordination

    PubMed Central

    Keller, Peter E.; Repp, Bruno H.

    2008-01-01

    The influence of integrated goal representations on multilevel coordination stability was investigated in a task that required finger tapping in antiphase with metronomic tone sequences (inter-agent coordination) while alternating between the two hands (intra-personal coordination). The maximum rate at which musicians could perform this task was measured when taps did or did not trigger feedback tones. Tones produced by the two hands (very low, low, medium, high, very high) could be the same as, or different from, one another and the (medium-pitched) metronome tones. The benefits of feedback tones were greatest when they were close in pitch to the metronome and the left hand triggered low tones while the right hand triggered high tones. Thus, multilevel coordination was facilitated by tones that were easy to integrate with, but perceptually distinct from, the metronome, and by compatibility of movement patterns and feedback pitches. PMID:18486931

  10. Hand Dominance and Common Hand Conditions.

    PubMed

    Lutsky, Kevin; Kim, Nayoung; Medina, Juana; Maltenfort, Mitchell; Beredjiklian, Pedro K

    2016-05-01

    The goals of this study were to (1) assess how frequently patients present for evaluation of common hand disorders in relation to hand dominance and (2) evaluate the effect of hand dominance on function in patients with these conditions. The authors hypothesized that (1) the majority of patients who seek evaluation would have a condition that affects the dominant hand, and (2) disability scores would be worse if the dominant hand is involved. They retrospectively reviewed the records of consecutive patients who presented for treatment to their institution with unilateral symptoms of 5 common disorders of the hand: carpal tunnel syndrome (CTS), de Quervain's tenosynovitis (DEQ), lateral epicondylitis (LE), hand osteoarthritis (OA), and trigger finger (TF). The authors assessed the effect of diagnosis and hand dominance on Disabilities of the Arm, Shoulder and Hand (DASH) scores. The study group comprised 1029 patients (379 men and 650 women) with a mean age of 59.5 years. Ninety percent were right-hand dominant. The dominant and nondominant hands were affected with relatively equal frequency for CTS, DEQ, OA, and TF (range, 45%-53%). Patients with LE had a significantly higher incidence of dominant hand involvement. Men had lower DASH scores than women by an average of 7.9 points, and DASH scores were significantly but slightly higher for the overall group (3.2 points) when the dominant side was affected. Men with LE and women with TF and OA had significantly higher DASH scores when their dominant extremity was affected. Common hand disorders such as CTS, DEQ, OA, and TF affect the dominant and nondominant hands in roughly equivalent proportions, whereas LE is more common on the dominant side. Dominant hand involvement results in significantly worse DASH scores, although the magnitude of this is relatively small. Women have significantly higher DASH scores than men for the conditions evaluated. [Orthopedics. 2016; 39(3):e444-e448.].

  11. Spontaneous eye blinks during creative task correlate with divergent processing.

    PubMed

    Ueda, Yoshiyuki; Tominaga, Atsuko; Kajimura, Shogo; Nomura, Michio

    2016-07-01

    Creativity consists of divergent and convergent thinking, with both related to individual eye blinks at rest. To assess underlying mechanisms between eye blinks and traditional creativity tasks, we investigated the relationship between creativity performance and eye blinks at rest and during tasks. Participants performed an alternative uses and remote association task while eye blinks were recorded. Results showed that the relationship between eye blinks at rest and creativity performance was compatible with those of previous research. Interestingly, we found that the generation of ideas increased as a function of eye blink number during the alternative uses task. On the other hand, during the remote association task, accuracy was independent of eye blink number during the task, but response time increased with it. Moreover, eye blink changes in participants who responded quickly during the remote association task were different depending on their resting state eye blinks; that is, participants with many eye blinks during rest showed little increasing eye blinks and achieved solutions quickly. Positive correlations between eye blinks during creative tasks and yielding ideas on the alternative uses task and response time on the remote association task suggest that eye blinks during creativity tasks relate to divergent thinking processes such as conceptual reorganization.

  12. Hand gesture guided robot-assisted surgery based on a direct augmented reality interface.

    PubMed

    Wen, Rong; Tay, Wei-Liang; Nguyen, Binh P; Chng, Chin-Boon; Chui, Chee-Kong

    2014-09-01

    Radiofrequency (RF) ablation is a good alternative to hepatic resection for treatment of liver tumors. However, accurate needle insertion requires precise hand-eye coordination and is also affected by the difficulty of RF needle navigation. This paper proposes a cooperative surgical robot system, guided by hand gestures and supported by an augmented reality (AR)-based surgical field, for robot-assisted percutaneous treatment. It establishes a robot-assisted natural AR guidance mechanism that incorporates the advantages of the following three aspects: AR visual guidance information, surgeon's experiences and accuracy of robotic surgery. A projector-based AR environment is directly overlaid on a patient to display preoperative and intraoperative information, while a mobile surgical robot system implements specified RF needle insertion plans. Natural hand gestures are used as an intuitive and robust method to interact with both the AR system and surgical robot. The proposed system was evaluated on a mannequin model. Experimental results demonstrated that hand gesture guidance was able to effectively guide the surgical robot, and the robot-assisted implementation was found to improve the accuracy of needle insertion. This human-robot cooperative mechanism is a promising approach for precise transcutaneous ablation therapy. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  13. Processing Coordinated Structures: Incrementality and Connectedness

    ERIC Educational Resources Information Center

    Sturt, Patrick; Lombardo, Vincenzo

    2005-01-01

    We recorded participants' eye movements while they read sentences containing verb-phrase coordination. Results showed evidence of immediate processing disruption when a reflexive pronoun embedded in the conjoined verb phrase mismatched the sentence subject. We argue that this result is incompatible with models of human parsing that employ only…

  14. Behavioral impact of unisensory and multisensory audio-tactile events: pros and cons for interlimb coordination in juggling.

    PubMed

    Zelic, Gregory; Mottet, Denis; Lagarde, Julien

    2012-01-01

    Recent behavioral neuroscience research revealed that elementary reactive behavior can be improved in the case of cross-modal sensory interactions thanks to underlying multisensory integration mechanisms. Can this benefit be generalized to an ongoing coordination of movements under severe physical constraints? We choose a juggling task to examine this question. A central issue well-known in juggling lies in establishing and maintaining a specific temporal coordination among balls, hands, eyes and posture. Here, we tested whether providing additional timing information about the balls and hands motions by using external sound and tactile periodic stimulations, the later presented at the wrists, improved the behavior of jugglers. One specific combination of auditory and tactile metronome led to a decrease of the spatiotemporal variability of the juggler's performance: a simple sound associated to left and right tactile cues presented antiphase to each other, which corresponded to the temporal pattern of hands movement in the juggling task. A contrario, no improvements were obtained in the case of other auditory and tactile combinations. We even found a degraded performance when tactile events were presented alone. The nervous system thus appears able to integrate in efficient way environmental information brought by different sensory modalities, but only if the information specified matches specific features of the coordination pattern. We discuss the possible implications of these results for the understanding of the neuronal integration process implied in audio-tactile interaction in the context of complex voluntary movement, and considering the well-known gating effect of movement on vibrotactile perception.

  15. Guideline Implementation: Hand Hygiene.

    PubMed

    Goldberg, Judith L

    2017-02-01

    Performing proper hand hygiene and surgical hand antisepsis is essential to reducing the rates of health care-associated infections, including surgical site infections. The updated AORN "Guideline for hand hygiene" provides guidance on hand hygiene and surgical hand antisepsis, the wearing of fingernail polish and artificial nails, proper skin care to prevent dermatitis, the wearing of jewelry, hand hygiene product selection, and quality assurance and performance improvement considerations. This article focuses on key points of the guideline to help perioperative personnel make informed decisions about hand hygiene and surgical hand antisepsis. The key points address the necessity of keeping fingernails and skin healthy, not wearing jewelry on the hands or wrists in the perioperative area, properly performing hand hygiene and surgical hand antisepsis, and involving patients and visitors in hand hygiene initiatives. Perioperative RNs should review the complete guideline for additional information and for guidance when writing and updating policies and procedures.

  16. Chapped hands (image)

    MedlinePlus

    Chapped hands can be sore and painful. Chapped hands may be soothed by the use of moisturizing lotions and the avoidance of excess exposure to water. If hands become badly chapped, hydrocortisone creams (available over the ...

  17. Hand splint - slideshow

    MedlinePlus

    ... this page: //medlineplus.gov/ency/presentations/100142.htm Hand splint - series—Indications To use the sharing features ... out of 4 Overview To begin making a hand dressing, place the injured hand around a cloth ...

  18. Following the Hand: The First Three Years of Life.

    ERIC Educational Resources Information Center

    Orion, Judy

    2001-01-01

    Discusses the development of the human hand from birth to age three as it contributes to the formation of human personality. Considers how parallels in eye, hand, brain, and motor skill development portray the evolving complexity and adaptation of the human grasp and illustrate Montessori theories about the relationship between physical experience…

  19. Neural constraints on eye motion in human eye-head saccades.

    PubMed

    Misslisch, H; Tweed, D; Vilis, T

    1998-02-01

    slit glasses, their EOMRs shrank mostly in the direction perpendicular to the slit, showing that altered vision can change the shape as well as the size of the EOMR. A recent, three-dimensional model of eye-head coordination can explain all these findings if we add to it a mechanism for adjusting the EOMR.

  20. Terminology used in research reports of developmental coordination disorder.

    PubMed

    Magalhães, Lívia C; Missiuna, Cheryl; Wong, Shirley

    2006-11-01

    A systematic search was performed of all articles from January 1995 to December 2005 published in peer-reviewed journals on children with developmental coordination disorder (DCD). Criteria were applied to ensure that articles included DCD so 319 articles were included in the analysis. Since the publication of a systematic search conducted in 1994, the number of publications in this field has greatly increased across countries and disciplines. The term DCD was used in 52.7% of the articles. Other terms were used less frequently: clumsy children (7.2%), developmental dyspraxia (3.5%), handwriting problems (3.1%), hand-eye coordination problems (2.8%), sensory integration dysfunction (2.5%), deficits in attention, motor control, and perception (2.5%), minor neurological dysfunction (2.2%), and several other scattered terms (23.5%). The data indicated that progress has been made in the usage of the term DCD, but a standardized approach has not yet been achieved. Without consistent use of the term DCD, there is limited communication of research results internationally, slowed progress in understanding the condition, and limited development of intervention and management programmes for children with DCD.

  1. Biomimetic hand exotendon device (BiomHED) for functional hand rehabilitation in stroke.

    PubMed

    Lee, Sang Wook; Landers, Katlin A; Park, Hyung-Soon

    2013-06-01

    Significant functional impairment of the hand is commonly observed among stroke survivors. In order to restore the functional use of the affected hand, we developed a biomimetic device that assists in generating functional movements of the hand. The device is actuated by exotendons that replicate the kinetic functional of the hand muscle-tendons, therefore it can reproduce the spatial finger joint coordination patterns of the functional manual tasks (e.g., power grip and pinch) with a reduced number of actuators. The system includes a thumb actuation mechanism, whose action is coordinated with finger exotendons to perform various manual tasks, thereby restoring the functional use of the hand. This paper presents the design of the device and the preliminary data of the functional movement generation by the system.

  2. In a demanding task, three-handed manipulation is preferred to two-handed manipulation

    NASA Astrophysics Data System (ADS)

    Abdi, Elahe; Burdet, Etienne; Bouri, Mohamed; Himidan, Sharifa; Bleuler, Hannes

    2016-02-01

    Equipped with a third hand under their direct control, surgeons may be able to perform certain surgical interventions alone; this would reduce the need for a human assistant and related coordination difficulties. However, does human performance improve with three hands compared to two hands? To evaluate this possibility, we carried out a behavioural study on the performance of naive adults catching objects with three virtual hands controlled by their two hands and right foot. The subjects could successfully control the virtual hands in a few trials. With this control strategy, the workspace of the hands was inversely correlated with the task velocity. The comparison of performance between the three and two hands control revealed no significant difference of success in catching falling objects and in average effort during the tasks. Subjects preferred the three handed control strategy, found it easier, with less physical and mental burden. Although the coordination of the foot with the natural hands increased trial after trial, about two minutes of practice was not sufficient to develop a sense of ownership towards the third arm.

  3. In a demanding task, three-handed manipulation is preferred to two-handed manipulation

    PubMed Central

    Abdi, Elahe; Burdet, Etienne; Bouri, Mohamed; Himidan, Sharifa; Bleuler, Hannes

    2016-01-01

    Equipped with a third hand under their direct control, surgeons may be able to perform certain surgical interventions alone; this would reduce the need for a human assistant and related coordination difficulties. However, does human performance improve with three hands compared to two hands? To evaluate this possibility, we carried out a behavioural study on the performance of naive adults catching objects with three virtual hands controlled by their two hands and right foot. The subjects could successfully control the virtual hands in a few trials. With this control strategy, the workspace of the hands was inversely correlated with the task velocity. The comparison of performance between the three and two hands control revealed no significant difference of success in catching falling objects and in average effort during the tasks. Subjects preferred the three handed control strategy, found it easier, with less physical and mental burden. Although the coordination of the foot with the natural hands increased trial after trial, about two minutes of practice was not sufficient to develop a sense of ownership towards the third arm. PMID:26912293

  4. HandsFree TLCMS

    SciTech Connect

    2004-07-30

    The HandsFreeTLCMS software is able to - control an x,y,z stage connected to the computer via USB interface - automatically form and maintain the liquid junction between a TLC plate and the sampling probe of a TLC/MS surface sampler unit - automatically accomplish multiple-lane scans over a TLC plate making able to sample the whole surface by a pre-defined, reproducible, automated method - analyze mass spectrometric data collected during the surface scans and make datafiles those contain x,y coordinates of surface spots (collected during the surface scans) and the corresponding mass signal intensities (integrated over a pre-defined m/z range) at those spots to produce 3-dimensional plots later in external graphic programs. - produce and save greyscale or color 2D pictures where X and Y axises of the picture correspond to the horizontal (x) and vertical (y) range of the scanned surface area and the color of a pixel is determined by the corresponding mass signal intensities (integrated over a pre-defined m/z range) at that X,Y spot

  5. Pain ameliorating effect of eye movement desensitization.

    PubMed

    Hekmat, H; Groth, S; Rogers, D

    1994-06-01

    This study explores the efficacy of eye movement desensitization and reprocessing (EMD/R) in the management of acute pain induced by hand exposures to ice water. Thirty participants were randomly assigned to one of the following interventions: (a) eye movement desensitization and reprocessing, (b) eye movement desensitization with music (EMD/M), and (c) control. The EMD/R participants focused on negative experiences associated with exposure to ice water, generated positive self-talk, and diverted their attention away from pain by focusing on a rapidly moving light on a monitor. The EMD with music group received eye movement desensitization coupled with preferred music. Repeated measures univariate and multivariate analysis of covariance was used to analyze the data. Results indicated that both procedures alleviated participants' pain to a similar degree and significantly more than the control, P < 0.05.

  6. Binocular Coordination during Reading and Non-Reading Tasks

    ERIC Educational Resources Information Center

    Kirkby, Julie A.; Webster, Lisa A. D.; Blythe, Hazel I.; Liversedge, Simon P.

    2008-01-01

    The goal of this review is to evaluate the literature on binocular coordination during reading and non-reading tasks in adult, child, and dyslexic populations. The review begins with a description of the basic characteristics of eye movements during reading. Then, reading and non-reading studies investigating binocular coordination are evaluated.…

  7. Hand washing and surgical hand antisepsis.

    PubMed

    Pirie, Susan

    2010-05-01

    Hand hygiene has always been an important element of perioperative practice and is a topic that has gained even more importance in recent years for healthcare workers. In the mid 19th century Semmelweis first noted the link between hospital acquired diseases and hand hygiene (Semmelweis 1847, NATN 2000). More recently, it has been established that continuous effective hand hygiene can significantly decrease the transmission of microorganisms, thus reducing cross infection rates of many hospital acquired infections (Pratt et al 2007).

  8. Functional eye movement disorders.

    PubMed

    Kaski, D; Bronstein, A M

    2017-01-01

    Functional (psychogenic) eye movement disorders are perhaps less established in the medical literature than other types of functional movement disorders. Patients may present with ocular symptoms (e.g., blurred vision or oscillopsia) or functional eye movements may be identified during the formal examination of the eyes in patients with other functional disorders. Convergence spasm is the most common functional eye movement disorder, but functional gaze limitation, functional eye oscillations (also termed "voluntary nystagmus"), and functional convergence paralysis may be underreported. This chapter reviews the different types of functional eye movement abnormalities and provides a practical framework for their diagnosis and management.

  9. [Dominance of cerebral hemispheres and visual space-hand localization].

    PubMed

    Baranowska-George, T; Kojder, I; Kowerska, D; Kopacka, W

    1990-10-01

    The visual space-hand localization from each eye and by each hand was examined by means of a localizer. Two kinds of examination were performed: one checked the initial, the other the postexercise localization. The dominance of the cerebral hemispheres was determined by psychological tests. No dependence of the behaviour of the visual hand localization on the domination of a given hemisphere was shown.

  10. Eye Carduino: A Car Control System using Eye Movements

    NASA Astrophysics Data System (ADS)

    Kumar, Arjun; Nagaraj, Disha; Louzardo, Joel; Hegde, Rajeshwari

    2011-12-01

    Modern automotive systems are rapidly becoming highly of transportation, but can be a web integrated media centre. This paper explains the implementation of a vehicle control defined and characterized by embedded electronics and software. With new technologies, the vehicle industry is facing new opportunities and also new challenges. Electronics have improved the performance of vehicles and at the same time, new more complex applications are introduced. Examples of high level applications include adaptive cruise control and electronic stability programs (ESP). Further, a modern vehicle does not have to be merely a means using only eye movements. The EyeWriter's native hardware and software work to return the co-ordinates of where the user is looking. These co-ordinates are then used to control the car. A centre-point is defined on the screen. The higher on the screen the user's gaze is, the faster the car will accelerate. Braking is done by looking below centre. Steering is done by looking left and right on the screen.

  11. How active gaze informs the hand in sequential pointing movements.

    PubMed

    Wilmut, Kate; Wann, John P; Brown, Janice H

    2006-11-01

    Visual information is vital for fast and accurate hand movements. It has been demonstrated that allowing free eye movements results in greater accuracy than when the eyes maintain centrally fixed. Three explanations as to why free gaze improves accuracy are: shifting gaze to a target allows visual feedback in guiding the hand to the target (feedback loop), shifting gaze generates ocular-proprioception which can be used to update a movement (feedback-feedforward), or efference copy could be used to direct hand movements (feedforward). In this experiment we used a double-step task and manipulated the utility of ocular-proprioceptive feedback from eye to head position by removing the second target during the saccade. We confirm the advantage of free gaze for sequential movements with a double-step pointing task and document eye-hand lead times of approximately 200 ms for both initial movements and secondary movements. The observation that participants move gaze well ahead of the current hand target dismisses foveal feedback as a major contribution. We argue for a feedforward model based on eye movement efference as the major factor in enabling accurate hand movements. The results with the double-step target task also suggest the need for some buffering of efference and ocular-proprioceptive signals to cope with the situation where the eye has moved to a location ahead of the current target for the hand movement. We estimate that this buffer period may range between 120 and 200 ms without significant impact on hand movement accuracy.

  12. Eye movements of vertebrates and their relation to eye form and function.

    PubMed

    Land, Michael F

    2015-02-01

    The types of eye movements shown by all vertebrates originated in the earliest fishes. These consisted of compensatory movements, both vestibular and visual, to prevent image motion, and saccades to relocate gaze. All vertebrates fixate food items with their heads to enable ingestion, but from teleosts onwards some species also use eye movements to target particular objects, especially food. Eye movement use is related to the resolution distribution in the retina, with eyes that contain foveas, or areas of high ganglion cell density, being more likely to make targeting eye movements, not seen in animals with more uniform retinas. Birds, in particular, tend mainly to use head movements when shifting gaze. Many birds also make translatory head saccades (head bobbing) when walking. It is common for animals to use both eyes when locating food items ahead, but the use of binocular disparity for distance judgment is rare, and has only been demonstrated in toads, owls, cats and primates. Smooth tracking with eyes alone is probably confined to primates. The extent of synchrony and directional symmetry in the movements of the two eyes varies greatly, from complete independence in the sandlance and chameleon, to perfect coordination in primates.

  13. Eye muscle test (image)

    MedlinePlus

    ... the extraocular muscles which results in uncontrolled eye movements. The test involves moving the eyes in six different directions in space to evaluate the proper functioning of the extraocular ...

  14. Eye Drop Tips

    MedlinePlus

    ... Involved News About Us Donate In This Section Eye Drop Tips en Español email Send this article ... the reach of children. Steps For Putting In Eye Drops: Start by tilting your head backward while ...

  15. Diabetic Eye Problems

    MedlinePlus

    ... too high. Over time, this can damage your eyes. The most common problem is diabetic retinopathy. It ... light-sensitive tissue at the back of your eye. You need a healthy retina to see clearly. ...

  16. Eye Injuries (For Parents)

    MedlinePlus

    ... and comfortable as possible until help arrives. continue Chemical Exposure Many chemicals, even those found around the house, can damage an eye. If your child gets a chemical in the eye and you know what it ...

  17. Recommended Sports Eye Protectors

    MedlinePlus

    ... Eye Emergencies How to Jump Start a Car Battery Safely Electronic Screens and Your Eyes Nutrition and ... External Resources The Cost of Vision Problems The Future of Vision Vision Problems in the U.S. Healthy ...

  18. LASIK Eye Surgery

    MedlinePlus

    ... conditions. These conditions include: Autoimmune disorders, such as rheumatoid arthritis Immunodeficiency conditions caused by immunosuppressive medications or HIV Persistent dry eyes Unstable vision due to medications, hormonal changes, pregnancy, breast-feeding or age Several eye conditions, such ...

  19. Diabetes and eye disease

    MedlinePlus

    ... have damage to the blood vessels in your eye, some types of exercise can make the problem worse. Check with your health care provider before starting an exercise program. Other eye problems that can occur in people with diabetes ...

  20. Infrared Eye: Prototype 2

    DTIC Science & Technology

    2016-06-07

    The Infrared (IR) Eye was developed with support from the National Search and Rescue Secretariat (NSS), in view of improving the efficiency of...airborne search-and rescue operations. The IR Eye concept is based on the human eye and uses simultaneously two fields of view to optimize area coverage and...within the wide field and slaved to the operator’s line of sight by means of an eye -tracking system. The images from both cameras are fused and shown