• Proceedings of the KOSOMBE Conference
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• v.1991 no.05
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• pp.28-30
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• 1991

A visual prosthesis for the blind based upon electrical stimulation of the visual cortex requires the development of an array of electrodes. To establish design specifications for such an electrode array, we have conducted psychophysical experiments with normally sighted subjects wearing a portable 'phosphene' simulator. The simulator consists of a small video camera, a monitor masked by an opaque perforated film, and optical lenses. The visual angle subtended by the masked monitor is $1.7^{\circ}$ or less. We measured visual acuity and reading rate as a function of the number of pixels and their spacing. Our results indicate that a phosphene image produced by 600 electrodes implanted in a $1\;cm^2$, area near the foveal projection on the visual cortex should provide a limited but useful visual sense for the profoundly blind.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2010.05a
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• pp.48-54
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• 2010

INTRODUCTION Interaction between temporal events at the millisecond level is important for visual and tactile interaction. OBJECT The aim of the present study is to identify any neural signature, as reflected in event-related potentials (ERP), for the integrative processes when the two sensory modalities are stimulated in synchrony as opposed to when they are stimulated separately. METHOD The basic strategy was to compare ERP signals obtained with simultaneous visual and tactile stimulation with a linear summation of ERP patterns obtained with each modality stimulated separately. Condition were presented, paired with various stimulus-onset-asynchronies (SOA) ranging from - 300 ms (tactile-first) to 300 ms (visual-first), and in trials where only one modality was stimulated alone. RESULT A positive deviation was located in observed ERP at C4 electrode (contralateral to the stimulated hand) at 200-400 ms, in comparison to the predicted ERP. The deviation was present at all SOAs other than -300ms (tactile-first) and 300 ms (visual-first). There was also a positive deviation at occipital leads at the 50-ms SOA (visual-first) trials. DISCUSSION It suggested that neural signatures of cross-modal integration occur within a limited time-window. The deviations were specifically localized at the contralateral somatosensory and visual cortices, indicating that the integration happens at or before the level of the primary cortices.

• Journal of Sasang Constitutional Medicine
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• v.22 no.1
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• pp.41-48
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• 2010

1. Objective There has been a few trials to diagnose Sasang Constitution by using EEG, but has not been studied intensively. For the purpose of practical diagnosis, the characteristics of EEG for each constitution should be studied first. Recently it has been shown that Sasang Constitution might be related to harm avoidance and novelty seeking in temperament and character profiles. Based on this finding, we propose a visual stimulation method to evoke a EEG response which may discriminate difference between constitutional groups. Through the experiment with this method, we tried to reveal the characteristics of EEG of each constitutional groups by the method of event-related potentials. 2. Methods: We used facial visual stimulation to verify the characteristics of EEG for each constitutional groups. To reveal characteristic in sensitivity and latency of response, we added several levels of noise to facial images. 6 male subjects(2 Taeeumin, 2 Soyangin, 2 Soeumin) participated in this study. All subjects are healthy 20's. To remove artifacts and slow modulation, we removed EOG contaminated data and renormalization is applied. To extract stimulation related components, normalized event-related potential method was used. 3. Results: From Oz channels, it is verified that facial image processing components are extracted. For lower level noise, components related to the visual stimulation were clearly shown in Oz, Pz, and Cz channels. Pz and Cz channels show differences among 3 constitutional groups in maximum around 200 msec. Especially moderate level of noise looks appropriate for diagnosis. 4. Conclusion: We verified that the visual stimulation with facial emotion might be a good candidate to evoke the differences between constitutional groups in EEG response. The differences shown in the experiment may imply that the process of emotion has distinct tendencies in latencies and sensitivity for each consitutional group. And this distinction might be related to the temperament profile of consitutional groups.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.661-664
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• 2002

A control of the body posture and movement is maintained by the vestibular system, vision, and proprioceptors. Afferent signals from those receptors are transmitted to the vestibular nuclear complex, and the efferent signals from the vestibular nuclear complex control the eye movement. The postural disturbance caused by loss of the vestibular function results in nausea, vomiting, vertigo and loss of craving for life. The purpose of this study is to develop a off-vertical rotatory system for evaluating the function of semicircular canals and otolith organs, selectively, and visual stimulation system for stimulation with horizontal, vertical and 3D patterns. The Off-vertical axis rotator which stimulates semicircular canals and otolith organs selectively is composed of a comportable chair, a DC servo-motor with reducer and a tilting table controlled by PMSM. And a double feedback loop system containing a velocity feedback loop and a position feedback loop is applied to the servo controlled rotatory chair system. Horizontal, vertical, and 3D patterns of the visual stimulation for applying head mounted display are developed. And wireless portable systems for optokinetic stimulation and recording system of the eye movement is also constructed. The Gain, phase, and symmetry is obtained from analysis of the eye movement induced by vestibular and visual stimulation. Detailed data were described.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06c
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• pp.291-296
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• 1998

In the experiment carried out on 20 college students, recorded were frontal, temporal and occipital EEG, skin conductance response, skin conductance level, heart rate and respiration rate during listening to two music fragments with different affective valences and white noise administered immediately after negative visual stimulation. Analysis of physiological patterns observed during the experiment suggests that affective auditory stimulation with music is able to selectively modulate autonomic and cortical activity evoked by preceding aversive visual stimulation and to restore initial baseline levels. On other hand, physiological responses to white noise, which does not possess emotion-eliciting capabilities, evokes response typical for orienting reaction after the onset of a stimulus and is rapidly followed by habituation. Observed responses to white noise were similar to those specific to attention only and had no evidence for any emotion-related processes. Interpretation of the obtained data is considered in terms of the role of emotional and orienting significance of stimuli, dependence of effects on the background physiological activation level and time courses of attention and emotion processes. Physiological parameters are summarized with regard to their potential utility in differentiation of psychological processes induced by auditory stimuli.

• Journal of Biomedical Engineering Research
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• v.10 no.2
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• pp.125-130
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• 1989

In the present study, we described a test to explore the function of optokinetic system which subjected to a full visual field stimulation using two different stimulus images patterns. Our results were interesting in a point of view that the stimulation image pattern had non- neglisible influence on the optokinetic response and that in a bidimensionnel image such as the randomly distributed spots images pattern the linearity of system was assured upto the stimulus velocity of about 50 deg/sec for normal subject. As for measuring human optokinetic after nystagmus, the regular stripes pattern was rather desirable than the randomly distributed spots pattern in this study.

• Journal of The Korean Society of Integrative Medicine
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• v.1 no.4
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• pp.9-14
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• 2013

Purpose : The purpose of this study was to investigate the effect of visual Auditory rhythmic stimulation(VARS) in gait ability and proprioception with chronic stroke patients. Twenty-one persons after six months post stroke participated in pre test-post test control. Method : The subjects were randomly assigned to a visual Auditory rhythmic stimulation(VARS) group (n=10) and control group (n=11). Training process was practiced with exercise on thirty minutes a day, three days a week for four weeks. To find out the effect, inspected the FRT(functional reach test) by static balance and TUG(timed up and go test) by dynamic balance. Results : In static balance, FRT distance was significantly different between two group. In dynamic balance, TUG time was significantly different between two group. This study showed that the VARS training increase a balance by postural adjustment of chronic stroke patients more than control group. And so, the VARS training of hemiplegic patients was very important to successive rehabilitation. Conclusion : A continuous examination of VARS training could practical used of physical therapy with exercise.

• Journal of Oral Medicine and Pain
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• v.47 no.4
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• pp.189-197
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• 2022

Purpose: Pain perception is affected by a wide range of contributing factors, including biological, psychological, and social factors. Although the provision of visual information could have a modulatory effect on pain perception, it is unclear whether such a visual effect might vary depending on the anatomical site and stimulation type. This study aimed to analyze the modulatory effect of visual information on the perception of sharp and dull pain in the face and hand and to assess the influence of individual fear levels on modulatory visual information. Methods: A total of 68 healthy male and female volunteers were recruited for this study. Pressure and pricking pain with and without visual information were induced on the masseter and thenar muscles, and alterations in pain threshold were evaluated. The survey was conducted using the Geop-Pain Questionnaire (GPQ). Results: The pricking pain threshold of the hand was significantly elevated when viewing the stimulated hand. This result indicated that the provision of visual information could decrease sensitivity to sharp pain in the hand. However, when correlating the GPQ score with the alteration in thresholds induced by visual information, no significant correlation was observed between the GPQ score and the threshold difference induced by visual information. This finding showed that the visual effect was not significantly affected by the fear level. Conclusions: This study showed that the effect of visual information on the pain threshold could vary according to the anatomical site and stimulation type. A better understanding of such a modulatory effect on pain perception might be useful for clinicians during painful therapeutic procedures.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1999.03a
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• pp.3-6
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• 1999

The study was performed to evaluate the sense of equilibrium by means of rotary chair system in middle school girls with dance learning. Control of equilibrium, which is the most important function in dancing, is maintained by vestibular, visual, and proprioceptive inputs. Experimental groups were divided into trained group with dance (experimental group, 13~14 ys, n=15) and untrained group (control group, 13~14 ys, n=15). experimental group was trained by programmed dancing for 12 weeks, 45 min/day and 5 day/week. Gain of eye movement was measured for vestibulocular reflex (VOR), visual vestibular stimulation (VVOR), optokinetic stimulation(OKN), and visual fixation (VFX). The gain of eye movement at higher than 0.08 hz was significant decrease in experimental group, and VVOR showed the similar fashion to VOR. The gain in OKN and VFX was not significant difference between experimental and control groups. These results suggest that programmed training of dancing improves control of balance by adaptation of the vestibular function, and rotary chair system would be useful to evaluate the sense of equilibrium ability.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1997.11a
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• pp.157-162
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• 1997

The purpose of this study was to develop a sinusoidal rotatory chair systim for evaluating the vestibular function in patients suffered from vertigo with vestibualr disorders. The sinusoidal rotatory chair system is composed of a rotatory chair systim and softwares. Maximum velocity of the rotatiry chair was upto 60 degree per second and frequency range was 0.01 to 0.64 Hz. To evaluate the vestibular function in vertigo patients, vestibuloocular reflex was measured by sinusoidal rotation of the whole body about vertical axis in the darkness, and optokinetic nystagmus, visual vestibuloocular reflex , and visual supression test were also performed. Eye movement was measured by means of a electronystgmograph amplifier through Ag-AgCI surface electrodes. Gain, phase, and symmetry were obtained from analysis of the eye movement ineuced by vestibular or visual stimulation. In healthy adults, sinusoidal rotation of the shole body produced nystagmus, of which gain was directly proportional to the velocity of stimulation. The gain of visual vestibuloocular reflex or optokinetic nystagmus, and it was suppressed markedly by visual suppression test. These results suggest that the sinusoieal rotatory chair systim which was developed by this study can evaluate the vestibular function quantitatively, also this system is very useful to diagnose and to dstimate the vestibualr function during recovery from vertigo