BACKGROUND AND OBJECTIVES: Vestibulo-ocular reflex and vestibulo-spinal reflex are induced by transmatoid galvanic stimulation of vestibular system. Nystagmus and body sway are result of each reflex. Recently, videooculograph possible to record a minute ocular movement was commonly used, vestibulo-ocular reflex induced by galvanic simualtion is easily documented. The purposes of this study are to evaluate the galvanic nystagmus in nomal persons in order to better understand the physiology of the vestibular system. MATERIALS AND METHODS: Eye movement of 20 neurootologic normal subjects by both side transmstoid galvanic stimulation (40cases) were analyzing by videonystagmography. RESULT: The direction of nystagmus in fast phase was to the negative electrode. Galvanic nystagmus was occured all normal subjects when stimulus intensity was more than 2mA. There was positive correlation between slow phase velocity(SPV) and electric current but negative correlation was noted between asymmery of SPV and electric current. CONCLUSION: It is suggested that the galvanic nystagmus test could be a new diagnostic tool for evaluation of vestibular status.
Electrodes ; Eye Movements ; Humans ; Physiology ; Reflex ; Reflex, Vestibulo-Ocular

As a classic eye movement method, electrooculogram (EOG) has been extensively used in many applications. There are many different types of eye movements and artifact in the EOG signal. Noise attenuation and signal separation have received special attention in the EOG research. In this paper, we introduce a novel Linear-nonlinear combinational filter based on weighted FIR-median-hybrid (WFMH) with the characteristic of the EOG signal. The result of the simulation shows that this filter has the property of removing random noise more efficiently when preserving sharp edges. Finally, it is shown that the new filter is effective in separating saccadic and eye blink in the EOG signal.
Electrooculography ; methods ; Eye Movements ; physiology ; Humans ; Signal Processing, Computer-Assisted

In this article, the implementation of eye movement tracking system includes three procedures: hardware acquisition, data extraction and overall analysis. The system is based on Camshift algorithm with an eye tracking module added, developed on VC++ 6.0. The system can track the eye movement effectively in simulated phosphene evaluation experiment based on prosthetic vision.
Algorithms ; Analysis of Variance ; Eye Movements ; physiology ; Prosthesis Design

Biomechanical Phenomena ; Eye Movements ; Neurons/physiology* ; Pursuit, Smooth ; Saccades

Even though retinal images of objects change their locations following each eye movement, we perceive a stable and continuous world. One possible mechanism by which the brain achieves such visual stability is to construct a craniotopic coordinate by integrating retinal and extraretinal information. There have been several proposals on how this may be done, including eye-position modulation (gain fields) of retinotopic receptive fields (RFs) and craniotopic RFs. In the present study, we investigated coordinate systems used by RFs in the lateral intraparietal (LIP) cortex and frontal eye fields (FEF) and compared the two areas. We mapped the two-dimensional RFs of neurons in detail under two eye fixations and analyzed how the RF of a given neuron changes with eye position to determine its coordinate representation. The same recording and analysis procedures were applied to the two brain areas. We found that, in both areas, RFs were distributed from retinotopic to craniotopic representations. There was no significant difference between the distributions in the LIP and FEF. Only a small fraction of neurons was fully craniotopic, whereas most neurons were between the retinotopic and craniotopic representations. The distributions were strongly biased toward the retinotopic side but with significant craniotopic shifts. These results suggest that there is only weak evidence for craniotopic RFs in the LIP and FEF, and that transformation from retinotopic to craniotopic coordinates in these areas must rely on other factors such as gain fields.
Animals ; Macaca ; Visual Fields ; Frontal Lobe/physiology* ; Eye Movements ; Brain

OBJECTIVES: To explore the difference of eye movement characteristics between uncooperative and cooperative subjects with mental disorder after cerebral trauma. METHODS: Thirty-nine subjects which needed psychiatric impairment assessment were selected. According to the binomial forced-choice digit memory test （BFDMT）, all subjects were divided into cooperative and uncooperative groups. The subjects were asked to take the image completion test from Wechsler adult intelligence scale. Meanwhile, the data of eye movement track, fixation, saccade, pupil and blink were recorded by the track system of eye movement. RESULTS: There were significantly differences （P<0.05） in the data of saccade between cooperative （10 cases） and uncooperative groups （29 cases）. The frequency, time, amplitude, acceleration of saccadic in uncooperative group were significantly higher than cooperation group. The saccade latencies of cooperation group increased more than uncooperative group. There was a significant difference （P<0.05） in total discrete distance, average distance and total time of fixation between two groups, while the average duration time, number and frequency of fixation had no significantly difference （P>0.05） between two groups. And the blink frequency of cooperation group was higher than uncooperative group. CONCLUSIONS Eye movement can be an objective index for the primary judgment of cooperation level.
Adult ; Eye Movement Measurements ; Eye Movements/physiology* ; Humans ; Intelligence Tests ; Saccades/physiology* ; Wechsler Scales

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.
Bionics ; Eye Movements ; physiology ; Fixation, Ocular ; physiology ; Head Movements ; physiology ; Humans ; Ocular Physiological Phenomena ; Orientation ; Photic Stimulation ; Reflex, Vestibulo-Ocular ; physiology ; Saccades ; physiology

Sleep is a highly organized and complicated state that is fundamental to life. We have an absolute need to sleep during about one-third of our lives. There are two types of sleep, non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. NREM sleep is divided into stages 1, 2, and 3 which is representing a degree of relative depth in sleep. Each sleep stage shows unique features including some variations in electroencephalographic waves, eye movements, and muscle tone. Although sleep pattern changes are associated with aging, how sleep physiology and sleep patterns change over an individual's life span is not well-defined. Circadian rhythms, which are the daily rhythms in physiology and behavior, regulate the sleep-wake cycle. Comprehensive understanding of normal sleep physiology should be very important to better understand not only the effects of sleep related diseases but also the impacts of pathological sleep on various diseases of other systemic organs. This review aims to enhance knowledge focused on normal sleep physiology and its regulation.
Aging ; Circadian Rhythm ; Eye Movements ; Muscles ; Neurobiology ; Physiology* ; Sleep Stages ; Sleep, REM

BACKGROUNDDevelopmental dyslexia (DD) is a disorder in which children with normal intelligence and sensory abilities show learning deficits in reading. Abnormal eye movements have been found in DD. However, eye-movement abnormalities during visual search among Chinese children with DD remain unknown. We aimed to identify the eyemovement characteristics and search efficiency of Chinese children with DD during visual search for targets of different conceptual categories, under same-category conditions.

METHODSWe compared 32 Chinese dyslexic children and 39 non-dyslexic children in visual search tasks, which were assessed using EyeLink II High-Speed Eye Tracker (SR Research Ltd., Canada). Letters, single Chinese characters, digits, Chinese phrases, figures and facial expressions were used as stimuli. Targets were similar to distractors in meaning, phonology and/or shape.

RESULTSA main effect of task on visual search scores and all eye-movement parameters were found. Search scores, average saccade amplitude and saccade distance were significantly smaller in the DD group than in the controls. An interaction between group and task was found for pupil diameter.

CONCLUSIONSUnlike normal readers, children with DD had a reduction in the visual attention span and search accuracy. Besides, children with DD could not increase their mental workload with increase in task difficulty. The conceptual category of the stimulus materials significantly impacts search speed, accuracy and eye-movement parameters.

Adolescent ; Asian Continental Ancestry Group ; Child ; Dyslexia ; physiopathology ; Eye Movements ; physiology ; Female ; Humans ; Male

As a new array processing technique, independent component analysis(ICA) is an effective means to resolve the blind source separation(BSS) problem. Based on the brief introductions of ICA theory and algorithm, we apply ICA to the removal of ocular artifacts from EEG recordings. The EEG data collected from the human scalp is actually the mixtures of some independent components. It is coincident with the basic assumptions of ICA. Compared with the traditional methods of artifacts elimination, ICA, a kind of spatial filter, is not restricted by the case of spectrum overlapping, and it has a good reservation of useful detail signals. In addition, the inverse weight matrix of ICA can be used to reflect the topographic structure of different independent sources of EEG.
Algorithms ; Artifacts ; Electroencephalography ; Eye Movements ; physiology ; Humans ; Signal Processing, Computer-Assisted