Search results for "Movements"
showing 10 items of 273 documents
Motion sickness induced by otolith stimulation is correlated with otolith-induced eye movements
2008
International audience; This article addresses the relationships between motion sickness (MS) and three-dimensional (3D) ocular responses during otolith stimulation. A group of 19 healthy subjects was tested for motion sickness during a 16 min otolith stimulation induced by off-vertical axis rotation (OVAR) (constant velocity 60 degrees /s, frequency 0.16 Hz). For each subject, the MS induced during the session was quantified, and based on this quantification, the subjects were divided into two groups of less susceptible (MS-), and more susceptible (MS+) subjects. The angular eye velocity induced by the otolith stimulation was analyzed in order to identify a possible correlation between sus…
The widening of the gaze cone in patients with social anxiety disorder and its normalization after CBT
2013
Gaze plays a crucial role in social interactions. Social Anxiety Disorder (SAD), which is associated with severe impairment of social interactions, is thus likely to exhibit disturbances of gaze perception. We conducted two experiments with SAD-patients and healthy control participants using a virtual head whose gaze could be interactively manipulated. We determined the subjective area of mutual gaze, the so-called gaze cone, and measured it prior to and after a psychotherapeutic intervention (Exp. 1). Patients exhibited larger gaze cones than control subjects. Exp. 2 varied the emotional expression of the virtual head. These data were validated using a real person (professional actor) as s…
Rifle-balancing in precision shooting:behavioral aspects and psychophysiological implication
2007
This study investigated sharpshooters' strategies to control their rifle stability during the aiming period. Six elite and six pre-elite shooters completed a simulated realistic shooting task (laser rifle), and their performance was evaluated from behavioral and psychophysiological perspectives. The analysis of the rifle's barrel movement, indexing the shooter's behavioral performance, supported the view that rifle-balancing is an essential determinant of superior shooting performance. The psychophysiological data, i.e. the brain slow potentials, suggested that the shooters applied different rifle-hold strategies; the elite shooters concentrated primarily on achieving a stable rifle positio…
Parafoveal previews and lexical frequency in natural reading: Evidence from eye movements and fixation-related potentials.
2019
Participants' eye movements and electroencephalogram (EEG) signal were recorded as they read sentences displayed according to the gaze-contingent boundary paradigm. Two target words in each sentence were manipulated for lexical frequency (high vs. low frequency) and parafoveal preview of each target word (identical vs. string of random letters vs. string of Xs). Eye movement data revealed visual parafoveal-on-foveal (PoF) effects, as well as foveal visual and orthographic preview effects and word frequency effects. Fixation-related potentials (FRPs) showed visual and orthographic PoF effects as well as foveal visual and orthographic preview effects. Our results replicated the early preview …
Human walking along a curved path. I. Body trajectory, segment orientation and the effect of vision.
2003
Task-related characteristics of gait and segment orientation during natural locomotion along a curved path have been described in order to gain insight into the neural organization of walking. The locomotor task implied continuous deviation from straight-ahead, thereby requiring continuous adjustment of body movement to produce and assist turn-related torques. Performance was compared to straight-ahead locomotion. Subjects easily reproduced both trajectories with eyes open (EO). The actual-to-required trajectory difference increased blindfolded (BF), more so during turning. Stride length was unchanged for the outer but decreased for the inner leg. The feet anticipated subsequent body rotati…
Training the Motor Cortex by Observing the Actions of Others During Immobilization
2014
International audience; Limb immobilization and nonuse are well-known causes of corticomotor depression. While physical training can drive the recovery from nonuse-dependent corticomotor effects, it remains unclear if it is possible to gain access to motor cortex in alternative ways, such as through motor imagery (MI) or action observation (AO). Transcranial magnetic stimulation was used to study the excitability of the hand left motor cortex in normal subjects immediately before and after 10 h of right arm immobilization. During immobilization, subjects were requested either to imagine to act with their constrained limb or to observe hand actions performed by other individuals. A third gro…
Emotional communication in the context of joint attention for food stimuli: Effects on attentional and affective processing
2014
Guided by distinct theoretical frameworks (the embodiment theories, shared-signal hypothesis, and appraisal theories), we examined the effects of gaze direction and emotional expressions (joy, disgust, and neutral) of virtual characters on attention orienting and affective reactivity of participants while they were engaged in joint attention for food stimuli contrasted by preference (disliked, moderately liked, and liked). The participants were exposed to videos of avatars looking at food and displaying facial expressions with their gaze directed either toward the food only or toward the food and participants consecutively. We recorded eye-tracking responses, heart rate, facial electromyogr…
Where is the locus of the lowercase advantage during sentence reading?
2016
While most models of visual word identification and reading posit that a word's visual codes are rapidly transformed onto case-invariant representations (i.e., table and TABLE would equally activate the word unit corresponding to "table"), a number of experiments have shown a lowercase advantage in various word identification and reading tasks. In the present experiment, we examined the locus of this lowercase advantage by comparing the pattern of eye movements when reading sentences in lowercase vs. uppercase. Each sentence contained a target word that was high or low in word-frequency. Overall, results showed faster reading times for lowercase than for uppercase sentences. More important,…
Analysis of visually guided eye movements in subjects after whiplash injury
2011
Abstract Objective The aims of present research were to analyze the visually guided eye movements of subjects suffering from the consequences of whiplash injury and the possibility to differentiate patients from feigning subject. We analyzed the role of video-nystagmography for clinical and forensic aspects. Methods It was a prospective case–control study. Detailed history was taken and patients were thoroughly investigated. Smooth pursuit and saccadic eye movements were assessed in 33 patients affected by imbalance following a whiplash injury. A control group of 20 subjects was also evaluated. All tests were executed in neutral neck position and after left and right trunk rotation. Results…
Bipedal distribution of human vestibular‐evoked postural responses during asymmetrical standing
2002
Galvanic vestibular stimulation (GVS) evokes responses in muscles of both legs when bilateral stimuli are applied during normal stance. We have used this technique to assess whether asymmetrical standing alters the distribution of responses in the two legs. Subjects stood either asymmetrically with 75% of their body weight on one leg or symmetrically with each leg taking 50% of their body weight. The net response in each leg was taken from changes in ground reaction force measured from separate force plates under each foot. The net force profile consisted of a small initial force change that peaked at approximately 200 ms followed by an oppositely directed larger component that peaked at ap…