Hand Movements In Response Research Articles

Persistent avoidance of virtual food in anorexia nervosa-restrictive type: Results from motion tracking in a virtual stopping task.

Food avoidance is central to patients with anorexia nervosa-restrictive type (AN-R). Competing accounts in experimental psychopathology research suggest that food avoidance may result from automatic, habitual responses or from elevated inhibitory control abilities. This study investigated behavioral trajectories of food avoidance in a novel virtual reality stopping task. Sixty patients with AN-R and 29 healthy controls with normal weight were investigated using a novel, kinematic task in virtual reality. We recorded spatial displacement in stop- and go-trials to virtual food and control objects. Inhibitory control abilities were operationalized by the VR task in stopping performance (i.e., interrupted movement in stop-trials), whereas we also measured habitual avoidance of virtual food across both go- and stop-trials (i.e., delayed movement relative to nonfood objects). In patients with AN-R, hand displacements were shorter to food versus nonfood across stop- and go-trials, reflected in a Stimulus × Group interaction. Healthy controls showed no differences. Importantly, the food-specific effect in AN-R was identical across stop- and go-trials, indicating habitual food avoidance. Moreover, stop error rates (i.e., stop-trials with response) were lower in patients with AN-R. The findings suggest food-specific habitual avoidance and heightened generalized inhibitory control in AN-R. The continuously delayed displacements during active hand movements across stop- and go-trials indicated the persistence of patients' avoidance of food. Experimental research investigates the mechanisms underlying mental disorders such as anorexia nervosa. In this study, we measured interrupted hand movements in response to food pictures or neutral pictures (shoes) in patients with anorexia nervosa and healthy controls. A virtual reality scenario was used. Findings indicated that patients were slower at approaching food, interrupted or not. Key mechanisms of food avoidance can be translated into habit-based treatment options in future research.

Spatio-temporal evolution of human neural activity during visually cued hand movements.

Making hand movements in response to visual cues is common in daily life. It has been well known that this process activates multiple areas in the brain, but how these neural activations progress across space and time remains largely unknown. Taking advantage of intracranial electroencephalographic (iEEG) recordings using depth and subdural electrodes from 36 human subjects using the same task, we applied single-trial and cross-trial analyses to high-frequency iEEG activity. The results show that the neural activation was widely distributed across the human brain both within and on the surface of the brain, and focused specifically on certain areas in the parietal, frontal, and occipital lobes, where parietal lobes present significant left lateralization on the activation. We also demonstrate temporal differences across these brain regions. Finally, we evaluated the degree to which the timing of activity within these regions was related to sensory or motor function. The findings of this study promote the understanding of task-related neural processing of the human brain, and may provide important insights for translational applications.

Abstract WP191: Ipsilesional Mu Sensorimotor Rhythms Track With Hand Function Recovery in Stroke Survivors

This research seeks to identify source localization of neuromechanical changes associated with gains in hand grip function following BCI intervention sessions for upper extremity motor recovery. Mu rhythm desynchronization (ERD) of contralateral brain motor areas is thought to occur during movement and changes in brain motor area ERD relate to changes in behavioral measures, hand grip function, with BCI intervention. N=16 right hemisphere survivors participated in 9-15 sessions with BCI. Participants executed hand movements in response to visual cues on a computer screen with the corresponding audio instructions (e.g., Left, Right, Rest). The sessions (i.e. pre and post BCI intervention) contained two runs, each consisting of 15 trials for rest, left hand, and right hand movements (i.e., 5 trials for each of the three conditions) presented in random order. Data from the pre and post conditions were then grand averaged. sLORETA estimates were calculated as follows: 1) Clean EEG data segmented (LEFT hand attempted movements and REST) separately for PRE and POST conditions. 2) Cross-spectra (MU[8-12 Hz]) were computed then averaged (i.e. 1 average per each subject separately for left, right and rest trials. 3) sLORETA of MU power estimates at 6239 cortical locations/voxels were obtained, normalized across subjects. In the sLORETA implementation, computations made in realistic head model using the MNI152 template, with 3D solution space restricted to cortical gray matter, as determined by the probabilistic Talairach atlas. The specific frequency band cross-spectra (frequency-domain) obtained from the average-reference potential data, were the inputs for source localization. 4) sLORETA estimates between the 2 conditions [Movement - Rest] were then calculated in cortical space. Pearson correlation of voxel-wise Mu ERD with the change in Hand Grip were calculated. A stronger Mu ERD in the ipsilesional primary motor cortical area (BA 4) at ‘post’ intervention (i.e., more negative values compared to ‘pre’) was associated with a greater change in hand grip (r=-0.435, p=0.046 [1-tailed]). Increases in functional recovery of the impaired upper extremity (Hand Grip) have a direct correlation with greater changes in Mu ERD of ipsilesional motor brain areas.

Hyperactivity of Basal Ganglia in Patients With Parkinson's Disease During Internally Guided Voluntary Movements.

The contribution of different brain areas to internally guided (IG) and externally triggered (ET) movements has been a topic of debate. It has been hypothesized that IG movements are performed mainly through the basal ganglia-thalamocortical loop while ET movements are through the cerebello-thalamocortical pathway. We hypothesized that basal ganglia activity would be modified in patients with Parkinson's disease during IG movement as compared with normal subjects. We used functional MRI (fMRI) to investigate the differences between IG and ET motor tasks. Twenty healthy participants and 20 Parkinson's disease patients (OFF-state) were asked to perform hand movements in response to sound stimuli (ET) and in advance of the stimuli (IG). We showed that ET movements evoked activation of a few large clusters in the contralateral motor areas: the sensorimotor and premotor cortex, supplementary motor area (SMA), insula, putamen, motor thalamus and ipsilateral cerebellum. IG movements additionally evoked activation of a large number of small clusters distributed in different brain areas including the parietal and frontal lobes. Comparison between the activity of Parkinson's disease patients and healthy volunteers showed few important differences. We observed that along with the activity of the posterior areas, an activation of the anterior areas of putamen was observed during IG movements. We also found hyperactivity of the ventral thalamus for both movements. These results showed that IG movements in PD patients were made with the involvement of both sensorimotor and associative basal ganglia-thalamocortical loops.

Pursuit eye movements enhance decision making and hitting accuracy in a go/no-go manual interception task

It is well established that eye and hand movements are closely coupled in space and time—the eye saccades to and fixates on task-relevant object locations and leads the hand during reaching, grasping, or pointing movements. However, the relation between smooth pursuit and hand movements in response to dynamic visual targets is less well understood. Here, we investigate the relation between smooth pursuit and interception performance in a go/no-go manual interception task. We focus on two aspects of performance: the decision whether or not to move the hand, and the accuracy of the interception. Observers (n=10) viewed a small target moving along a linear path that either projected into a strike zone (hit) or went past it (miss); observers were instructed to intercept only in hit trials, and to not move their hand in miss trials. The target was shown for the full path to the strike zone, or for ¼, ½, or ¾ of the full trajectory. Eye movements were manipulated in separate blocks by instructing observers to maintain fixation on a stationary fixation cross, randomly positioned at three locations along the trajectory, or to move their eyes freely. Across conditions, better and faster pursuit (lower 2D position error, higher eye velocity) and more accurate fixation were linked to better decision and hitting accuracy. Importantly, engaging in smooth pursuit eye movements as compared to fixation resulted in a significant performance improvement across all observers. This pursuit benefit was of the same magnitude (8% average improvement in pursuit vs. fixation) with regard to decision making and hitting accuracy. These results underline the critical importance of smooth pursuit in guiding movement decisions and execution. They also imply that efference-copy signals, generated by the pursuit system, act early on the perceptual system to inform the decision whether or not to initiate a movement. Meeting abstract presented at VSS 2018

Complementary Hand Responses Occur in Both Peri- and Extrapersonal Space.

Human beings have a strong tendency to imitate. Evidence from motor priming paradigms suggests that people automatically tend to imitate observed actions such as hand gestures by performing mirror-congruent movements (e.g., lifting one’s right finger upon observing a left finger movement; from a mirror perspective). Many observed actions however, do not require mirror-congruent responses but afford complementary (fitting) responses instead (e.g., handing over a cup; shaking hands). Crucially, whereas mirror-congruent responses don't require physical interaction with another person, complementary actions often do. Given that most experiments studying motor priming have used stimuli devoid of contextual information, this space or interaction-dependency of complementary responses has not yet been assessed. To address this issue, we let participants perform a task in which they had to mirror or complement a hand gesture (fist or open hand) performed by an actor depicted either within or outside of reach. In three studies, we observed faster reaction times and less response errors for complementary relative to mirrored hand movements in response to open hand gestures (i.e., ‘hand-shaking’) irrespective of the perceived interpersonal distance of the actor. This complementary effect could not be accounted for by a low-level spatial cueing effect. These results demonstrate that humans have a strong and automatic tendency to respond by performing complementary actions. In addition, our findings underline the limitations of manipulations of space in modulating effects of motor priming and the perception of affordances.

Mapping the structure of perceptual and visual–motor abilities in healthy young adults

The ability to quickly detect and respond to visual stimuli in the environment is critical to many human activities. While such perceptual and visual–motor skills are important in a myriad of contexts, considerable variability exists between individuals in these abilities. To better understand the sources of this variability, we assessed perceptual and visual–motor skills in a large sample of 230 healthy individuals via the Nike SPARQ Sensory Station, and compared variability in their behavioral performance to demographic, state, sleep and consumption characteristics. Dimension reduction and regression analyses indicated three underlying factors: Visual–Motor Control, Visual Sensitivity, and Eye Quickness, which accounted for roughly half of the overall population variance in performance on this battery. Inter-individual variability in Visual–Motor Control was correlated with gender and circadian patters such that performance on this factor was better for males and for those who had been awake for a longer period of time before assessment. The current findings indicate that abilities involving coordinated hand movements in response to stimuli are subject to greater individual variability, while visual sensitivity and occulomotor control are largely stable across individuals.

Hand movements with a phase structure and gestures that depict action stem from a left hemispheric system of conceptualization.

The present study addresses the previously discussed controversy on the contribution of the right and left cerebral hemispheres to the production and conceptualization of spontaneous hand movements and gestures. Although it has been shown that each hemisphere contains the ability to produce hand movements, results of left hemispherically lateralized motor functions challenge the view of a contralateral hand movement production system. To examine hemispheric specialization in hand movement and gesture production, ten right-handed participants were tachistoscopically presented pictures of everyday life actions. The participants were asked to demonstrate with their hands, but without speaking what they had seen on the drawing. Two independent blind raters evaluated the videotaped hand movements and gestures employing the Neuropsychological Gesture Coding System. The results showed that the overall frequency of right- and left-hand movements is equal independent of stimulus lateralization. When hand movements were analyzed considering their Structure, the presentation of the action stimuli to the left hemisphere resulted in more hand movements with a phase structure than the presentation to the right hemisphere. Furthermore, the presentation to the left hemisphere resulted in more right and left-hand movements with a phase structure, whereas the presentation to the right hemisphere only increased contralateral left-hand movements with a phase structure as compared to hand movements without a phase structure. Gestures that depict action were primarily displayed in response to stimuli presented in the right visual field than in the left one. The present study shows that both hemispheres possess the faculty to produce hand movements in response to action stimuli. However, the left hemisphere dominates the production of hand movements with a phase structure and gestures that depict action. We therefore conclude that hand movements with a phase structure and gestures that represent action stem from a left hemispheric system of conceptualization.

The ability of bispectral index to detect intra‐operative wakefulness during isoflurane/air anaesthesia, compared with the isolated forearm technique

Clinical signs are unreliable for guiding anaesthetic administration and it is suggested that using the bispectral index can improve anaesthetic delivery. In the current study, isoflurane administration was guided to a bispectral index range of 55-60. Intra-operative responsiveness, as assessed by the isolated forearm technique, was compared with whether the bispectral index predicted/identified a patient's appropriate hand movements in response to commands. Thirty-four women underwent major gynaecological surgery with isoflurane/air and atracurium. Eleven women responded on 32 occasions with appropriate hand movements to commands given during surgery, of which the bispectral index detected 17 (sensitivity 53%). The bispectral index suggested consciousness 660 times in the absence of any movement responses (specificity 69%). The positive predictive value of the bispectral index was 3%. The median (IQR [range]) bispectral index value associated with an intra-operative response was significantly lower than that associated with eye opening after surgery: 60 (50-68 [36-83]) vs 77 (75-84 [59-90]), respectively (p = 2.25 × 10(-8)). Conversely, end-tidal isoflurane concentration was significantly higher at intra-operative response than at eye opening: 0.3 (0.3-0.4 [0.2-0.9]) vs 0.2 (0.1-0.2 [0.1-0.3]), respectively (p = 7.36 × 10(-8)). For patients who responded more than once during surgery, the bispectral index value associated with a response was not constant. No patient had recall for surgery or the taped commands, and only one could remember dreaming (a good dream). Titrating isoflurane to target a bispectral index range of 55-60 may result in an unacceptable number of patients who are conscious during surgery (albeit without recall).

A Study of Comparison of Implicit Learning in Post Stroke and Age-Matched Elderly Subjects

Background: A motor skill can be learnt implicitly without awareness of what is being learnt. There is inadequate evidence available whether adults with stroke can learn a motor skill implicitly. Aim: To examine the ability of adults who had unilateral stroke to learn implicitly a perceptual motor task and to compare them with age matched elderly subjects. Settings and Design: This was a prospective experimental study. 30 subjects with unilateral stroke were compared with 30 age -matched elderly subjects for speed of performance of a serial response time task(SRT). Materials and method: Subjects were asked to perform sequences of hand movements in response to target lights in 2 conditions: a patterned sequence and a random sequence. They were not given explicit knowledge of 2 conditions. The SRT to perform both patterned and random sequence activity was measured and comparison was done between both groups. On second day SRT of patterned sequence activity was measured for both groups to test retention. Results: The mean SRT for both groups showed statistically significant decrease with patterned sequence(mean difference-elderly:3.745, stroke:5.108) increase with random sequence (mean difference-elderly:2.792, stroke:3.592) and again decrease with reintroduction of patterned sequence(mean difference-elderly:1.762,stroke:2.423). There was statistically significant retention of implicit learning in both groups. Conclusion: Implicit Learning of Serial Response Time Task is preserved in post Stroke subjects since both the groups showed the similar trend of performance in all the blocks, however, speed of performance of post stroke subjects was slower than that of normal elderly subjects.

Visuomotor Adaptation Does Not Recalibrate Kinesthetic Sense of Felt Hand Path

Motor control relies on multiple sources of information. To estimate the position and motion of the hand, the brain uses both vision and body-position (proprioception and kinesthesia) senses from sensors in the muscles, tendons, joints, and skin. Although performance is better when more than one sensory modality is present, visuomotor adaptation suggests that people tend to rely much more on visual information of the hand to guide their arm movements to targets, even when the visual information and kinesthetic information about the hand motion are in conflict. The aim of this study is to test whether adapting hand movements in response to false visual feedback of the hand will result in the change or recalibration of the kinesthetic sense of hand motion. The advantage of this cross-sensory recalibration would ensure on-line consistency between the senses. To test this, we mapped participants' sensitivity to tilted and curved hand paths and then examined whether adapting their hand movements in response to false visual feedback affected their felt sense of hand path. We found that participants could accurately estimate hand path directions and curvature after adapting to false visual feedback of their hand when reaching to targets. Our results suggest that although vision can override kinesthesia to recalibrate arm motor commands, it does not recalibrate the kinesthetic sense of hand path geometry.

Modifications of cognitive and motor tasks affect the occurrence of event‐related potentials in the human cortex

This study concerns the question of how task modification affects the frequency occurrence of event-related potentials (ERP) inside the active cortical areas. In 13 candidates for epilepsy surgery, 156 sites in the temporal (74), frontal (73), and parietal (9) cortices were recorded by means of depth and subdural electrodes. Four modifications of the somatosensory evoked P3-like potentials were performed; (i) an oddball paradigm with silent counting of target stimuli (P3c); (ii) an oddball paradigm with a hand movement in response to target stimuli (P3m); (iii) an S1-S2 paradigm, ERP in the P300 time window after the S2 stimulus, with silent counting of target stimuli (S2c), and (iv) an S1-S2 paradigm with a hand movement in response to target stimuli (S2m). In comparing the oddball paradigms with the S1-S2 (contingent negative variation, CNV) paradigms, four regions emerge that are significantly linked with the oddball P3; the prefrontal cortex, the cingulate, the amygdalo-hippocampal complex, and the lateral temporal cortex. A prominent role of the cingulate and the fronto-orbital cortex in the cognitive processing of movement was supported when tasks with identical cognitive loads but different required responses were compared. Even relatively simple cognitive tasks activate many cortical regions. The investigated areas were activated in all tests; however, small regions in each field were active or inactive in relation to the nature of the task. The study indicates a variable and task-dependent internal organization of a highly complex and widely distributed system of active cortical areas.

Stopping eye and hand movements: Are the processes independent?

To explore how eye and hand movements are controlled in a stop task, we introduced effector uncertainty by instructing subjects to initiate and occasionally inhibit eye, hand, or eye + hand movements in response to a color-coded foveal or tone-coded auditory stop signal. Regardless of stop signal modality, stop signal reaction time was shorter for eye movements than for hand movements, but notably did not vary with knowledge about which movement to cancel. Most errors on eye + hand stopping trials were combined eye + hand movements. The probability and latency of signal respond eye and hand movements corresponded to predictions of Logan and Cowan's (1984) race model applied to each effector independently.

Implicit Learning of a Perceptual-Motor Skill After Stroke

A motor skill can be learned implicitly, without awareness of what is being learned. The purpose of this study was to examine the ability of adults who had unilateral stroke to learn implicitly a perceptual-motor task. Subjects were 47 people who were poststroke and 36 control subjects. Participants performed sequences of hand movements in response to target lights in 2 conditions: a patterned sequence and a random sequence. Participants were not given explicit knowledge of the presence of the 2 conditions. Those who had stroke performed with the upper-extremity ipsilateral to the lesion. Subjects who had stroke performed more slowly than control subjects. For both groups, times decreased with practice of the patterned sequence, increased with introduction of the random sequence, and decreased again with reintroduction of the patterned sequence. Group differences persisted in a retention test given the next day of the patterned sequence, and both groups showed decreased times over the course of the retention test. People with stroke are able to learn a perceptual-motor task even without explicit instructions regarding the patterned sequence embedded in the task.

Quantitative evaluation of two methods of control of bilateral stimulated hand grasps in persons with tetraplegia.

Electrical stimulation has been applied to the paralyzed muscles of both hands of two persons with tetraplegia using percutaneous and implantable electrodes. Two separate methods of user control were being investigated. The first monitored the myoelectric signals from the user's own sternocleidomastoid muscles and the second monitored wrist joint angle. These signals were used as commands to modify the stimulated grasps. The hands were instrumented to detect the degree of hand closure and grip force and the users matched these to specific target parameters using the controller during tracking tasks. Performance in these tracking tasks was measured quantitatively. Wrist control was found to be less sensitive to the direction of hand opening/closing required than the myoelectric control. The user's performance with the myoelectric control demonstrated sensitivity to the target size and the speed of hand movement in response to the command control. The wrist controller required less training than the myoelectric controller for users to become proficient in its use. Based on these results, the wrist controller and the myoelectric controller both provide successful control of bilateral hand grasp and release. Of the two controllers, the wrist controller is likely to provide the greater ease of use, although it is only available to the population of users with active wrist extension.

Visually guided motor imagery activates sensorimotor areas in humans

Stimulus-related changes in ongoing electroencephalography (EEG) over sensorimotor areas were investigated during a visually cued motor imagery task. Four subjects were instructed to imagine one-sided hand movements in response to visual cue stimuli. The EEG was recorded from central areas using 27 electrodes set at distances of 2.5 cm. The method of common spatial filters was used to extract discriminatory information of EEG patterns recorded during the two motor imagery conditions. Single EEG trials were classified in intervals of 250 ms for a 8-s period starting 3 s prior to stimulus presentation. The results suggest that perception of the visual cue stimulus modifies oscillations in sensorimotor areas specific to the indicated hand starting as soon as 250–500 ms after stimulus onset.

Rule-dependent neuronal activity in the prefrontal cortex.

We studied single-neuron activity in the prefrontal cortex (PF) while a monkey performed a task according to two different rules, termed conditional and spatial. The monkey viewed a video screen, and its task required a hand movement in response to the dimming of a light spot. There were four light spots on the screen: right, left, up, and down from the center. Only one of the four spots dimmed, and the degree of dimming was slight. Accordingly, the monkey needed to foveate the "correct" light spot to detect the dimming. A visual cue indicated which of the four light spots would be deemed correct and, thus, would dim on each trial. The sequence of events was as follows: a fixation spot appeared at the center of the screen; then, a cue appeared twice at one of the four potential target locations; then, the four target spots appeared; and, finally, one of them dimmed. Except for the color of an initial fixation point, the cues, their locations, and other events were identical for the conditional and spatial rules. The rules differed in one essential way. For the conditional rule, nonspatial attributes of the visual cue indicated which of the four light spots would dim, and the cue's location was irrelevant. For the spatial rule, the cue's location determined the correct target on that trial. The light spot at the location of the cue always dimmed, regardless of which cue appeared there. Our sample included 221 PF neurons showing significant task-related activity modulation, distributed among dorsal, dorsolateral, and ventral PF regions. Between one-third and one-half of the sample in each of those regions showed statistically significant activity differences that could be attributed to the rule. Selectivity for cues and/or their locations was common. However, there was no significant regional segregation of such selectivity. These data support the hypothesis that PF plays a role in the guidance of behavior according to previously learned rules.

The Effect of Age-Related Stereotypes on Response Initiation and Execution

In 2 experiments, the authors investigated the effects of positive and negative stereotypes of older adults on response initiation and execution. College students were first primed with the word young or the word old, and then produced an aimed hand movement in response to a positive or negative trait. Results of the 1st experiment indicated that the participants produced the fastest and most forceful movements when the word “old” primed negative traits; they produced the slowest and least forceful responses when the word old primed positive traits. In a 2nd experiment, the authors replicated these effects by using only the prime old. The results suggest that ageist responses extend beyond reaction time in a social judgment task.

Correlates of sequential elements of bimanual behavior in the neuronal activity of the neostriatum in monkeys.

Neuron spike activity was recorded in the putamen of monkeys trained to perform bimanual operant behavior consisting of nine separate steps. Neuronal reactions were present at all steps: in 52-62% of cases during movement, and in 27-36% of cases during responses to the trigger and conditioned signals and as the monkeys decided which was the working hand. The proportion of inhibitory responses to the trigger stimulus was 9%, while inhibitory reactions accounted for 68% of reactions during hand movement in response to the conditioned signal, 33% of reactions when this same hand was used to collect food reinforcement, and 33% of reactions during simultaneous movement of both hands. Reactions significantly differentiating between right- and left-sided tasks were seen at all stages of working-hand decision-taking and in reactions to the signal indicating the correctness of the selection, but were not seen for reactions to the conditioned signal or for activity accompanying movements of one of the animal's hands. These data provide evidence indicating that each step of the complex operant behavior, individual systems of putamen neuronal reactions were created with qualitatively different integral sensitivity to instantaneous behavior.

Attention Allocation During Manual Movement Preparation and Execution

Three experiments investigated the role of visuospatial attention in the relationship between perception and action. Participants performed goaldirected hand movements in response to central or peripheral visual cues. Identification performance was measured for letters that were briefly presented at different locations and time delays relative to the beginning of movement preparation or execution. Letter identification in the plane of movement varied with concurrent motor planning complexity, but similar hemifield differences were obtained irrespective of whether or not directional planning was required (Experiment 1). Independent of movement direction, identification in the hemifield contralateral to the active hand improved relative to ipsilateral performance (Experiment 2). Peripheral movement cues induced holistic motor planning, but hemifield differences for probe identification persisted (Experiment 3). These results violate predictions of a premotor theory of attention (Rizzolatti, R iggio, & Sheliga, 1994).