• Science of Emotion and Sensibility
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• v.27 no.2
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• pp.81-90
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• 2024

In this study, we aimed to determine the effect on cerebral blood vessels of various stimulus intensities using transcutaneous electrical nerve stimulation (TENS). In particular, we wanted to monitor changes in blood flow and structural changes in the blood vessels in the common carotid artery (CCA) through low-intensity electrical stimulation that can cause non-perceptual sensory stimulation. Twenty-four healthy adults in their 20s participated in this study. Three stimulus intensities (below the sensory threshold, at the sensory threshold, and above the sensory threshold) were applied in random order. Changes in blood flow velocity according to the intensity of TENS stimulus were measured by placing the Doppler ultrasound transducer 1 cm below the CCA bifurcation, and the vascular structure was measured using B-mode imaging. C-mode Doppler and B-mode images were acquired before, during, and after the intervention for each stimulus, and changes in blood pressure were measured in each session. As a result, it was confirmed that peak systolic velocity (PSV) decreased significantly after the intervention in non-perceived sensory stimulation below the threshold, compared to other thresholds (p = .008). In particular, the PSV decreased by 3.04% on average compared to before stimulation (p = .011). However, there was no significant change in the CCA diameters before and after stimulation at all intensities. It was found that short-term, non-perceptual sensory stimulation was effective in reducing the blood flow rate without causing significant changes in either the blood vessel diameter or blood pressure. This change appears to be caused by a decrease in blood flow due to the effect of subtle vasodilation at non-perceptual sensory stimulation, and at stimulation intensity higher than that, the sympathetic nerves in the blood vessels are stimulated excessively and the blood vessels constrict. Therefore, this study can be rated as an important attempt to control blood flow through stimulation without such a psychological burden and sensory discomfort in the carotid area.

• Science of Emotion and Sensibility
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• v.21 no.4
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• pp.91-102
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• 2018

Although accurate time perception is necessary to properly respond to the environment, it was discovered that non-temporal features also affect time perception. Previous studies have identified various factors that affect time perception, but there was no attempt to directly investigate the possible effects of the distance between participants and the stimuli on time perception. The current study examined the effects of viewing distance on time perception, by considering the retinal, physical, and perceived size of the stimuli. The viewing distance had no effect when either the physical size or the perceived size of the stimulus was the same. Viewing distance was found only to have an effect when the retinal size of the stimulus was the same. This effect might be a size effect rather than a distance effect because as the viewing distance increases the size should also increase to maintain the retinal size. These results imply that temporal perceptual constancy is preserved irrespective of the viewing distance, when distance information is not limited.

• Korean Journal of Cognitive Science
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• v.34 no.2
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• pp.111-151
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• 2023

It is reported that binge drinkers show cognitive impairment similar to alcohol use disorder patients. A previous studies using neuropsychological tests and brain imaging techniques to investigate the visual perception of alcohol use disorder patients reported that they had global-local visual perception defects. Although the neurological basis for the global-local visual perception deficit in the heavy drinking group has been presented, there are no studies to date that have investigated the global-local visual perception in the heavy drinking group. This study investigated local-biased visual perception in female college students with binge drinking (BD) using event-related potentials (ERPs). Based on the scores of the Korean version of Alcohol Use Disorder Identification Test and the Alcohol Use Questionnaire, participants were assigned into BD (n=25) and non-BD (n=25) groups. Local-global visual processing was assessed using a local-global paradigm, in which large stimuli (global level) composed of small stimuli (local level) were presented. The stimuli presented at global and local levels were either congruent or incongruent. The behavioral results exhibited that the BD and non-BD groups did not differ in terms of accuracy and response time. In terms of ERPs, the BD and non-BD groups did not show difference in N100, P150 and N200 amplitude. However, the BD group showed significantly smaller P300 amplitude than non-BD group especially in the local condition. In addition, a negative correlation between P300 amplitude and binge drinking score was observed, i.e., severer binge drinking smaller P300 amplitude. The P300 is known to reflect cognitive inhibition and attentional allocation. In the global-local paradigm, the local condition required to attend to local target while ignoring global non-target. Therefore, the present results indicate that female college students with BD do not have local-biased visual processing, instead they seem to have difficulties in inhibition of irrelevant stimuli.

• Science of Emotion and Sensibility
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• v.25 no.1
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• pp.79-90
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• 2022

IThe perception of sub-second duration through the visual sensory system is affected by non-temporal characteristics (factors other than the duration of the stimulus). However, studies have shown that if distance information is abundant and size constancy maintained, the duration of the target is constantly perceived. The current study examined the relationship between size and time perception constancy in a three-dimensional environment with limited distance information. A device was constructed to limit the participants' bilateral and monocular cues. This prevented participants from maintaining size constancy, resulting in size illusions that could not accurately perceive physical size. In Experiment 1, the size of the physical stimulus of reference and test stimuli were the same at all viewing distances. The results suggest that, despite the same physical size, stimuli with close observations were perceived to be greater and lasted longer. In Experiment 2, the retinal size of the reference stimuli and test stimuli was controlled equally at all viewing distances. As a result, although the physical size of the stimuli increased as the observation increased, the perceived size of all the stimuli was the same. Therefore, the duration of the target was constantly perceived at all viewing distances. The results of this study demonstrate that even when distance information is limited, time perception is affected by the perceived size of the object. It also suggests that when rich distance information exists, the duration of the object can be constantly perceived even if the observation distance varies.

• Proceedings of the KSLP Conference
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• 1999.11a
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• pp.182-182
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• 1999

Nasometer를 통해 얻은 비음치(nasalance score)는 객관적일 뿐만 아니라 훈련된 언어임상가가 청지각적으로 판단한 비음도와 상관관계가 높기 때문에, 공명장애 진단의 보조자료로 유용하다. 그러나 비음치는 자극어에 따라 다양한 수치를 보이므로 공명장애의 진단을 위해서는 타당하고 신비로운 자극어의 개발이 요구되고 있다 따라서 본 연구는 비음치에 영향을 미치는 주요한 음운 환경이 무엇인지 살펴보고, 무의미 1음절어와 유의미 문장 자극어 중 어떤 것이 더 신뢰로운지 알아보아, 비음치 측적을 위한 자극어 개발에 기초를 마련하고자 하였다. (중략)

• Korean Journal of Cognitive Science
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• v.20 no.1
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• pp.51-77
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• 2009

Using a modified Posner's cue-target paradigm, we investigated whether negative cues attract more attention than neutral cues in anxious people. Previous studies used commonly an unbalanced proportion of valid and invalid trials(75% vs. 25% respectively). But in the present study, an equivalent proportion of valid and invalids trials was used for measuring detection speed of cues without participant's expectancy caused by the unbalanced proportion. Emotional words(Experiment 1) and facial expressions(Experiment 2) were used as cues for target locations. The result of Experiment 1 and 2 showed that threatening cues facilitated target detection in valid trials and interfered with it in invalid trials in anxious participants and a, reverse response patterns were found in non-anxious participants. This indicates that threatening cues attract more attention to the cued location in anxious people and in contrast, non-anxious people avoid threatening stimuli. In Experiment 3, we investigated the difference of validity effect across anxiety levels. The results showed that anxious participants gave less attention to cued location when the cues were non-informative whereas non-anxious participants gave more attention to cued locations in the same condition. We discussed two kinds of cognitive bias caused by anxiety levels: attentional bias and proportion related bias.

• Korean Journal of Cognitive Science
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• v.34 no.3
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• pp.181-196
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• 2023

Size, velocity, and time equivalence are mechanisms that allow us to perceive objects in three-dimensional space consistently, despite errors on the two-dimensional retinal image. These mechanisms work on common cues, suggesting that the perception of motion distance, motion speed, and motion time may share common processing. This can lead to the hypothesis that, despite the spatial nature of visual stimuli distorting temporal perception, the perception of motion speed and the perception of motion duration will tend to oppose each other, as observed for objects moving in the environment. To test this hypothesis, the present study measured perceived speed using Müller-Lyer illusion stimulus to determine the relationship between the time-perception consequences of motion stimuli observed in previous studies and the speed perception measured in the present study. Experiment 1 manipulated the perceived motion trajectory while controlling for the retinal motion trajectory, and Experiment 2 manipulated the retinal motion trajectory while controlling for the perceived motion trajectory. The result is that the speed of the inward stimulus, which is perceived to be shorter, is estimated to be higher than that of the outward stimulus, which is perceived to be longer than the actual distance traveled. Taken together with previous time perception findings, namely that time perception is expanded for outward stimuli and contracted for inward stimuli, this suggests that when the perceived trajectory of a stimulus manipulated by the Müller-Lyer illusion is controlled for, perceived speed decreases with increasing duration and increases with decreasing duration when the perceived distance of the stimulus is constant. This relationship suggests that the relationship between time and speed perceived by spatial cues corresponds to the properties of objects moving in the environment, i.e, an increase in time decreases speed and a decrease in time increases speed when distance remains the same.

• Science of Emotion and Sensibility
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• v.21 no.3
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• pp.151-164
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• 2018

The appropriate interpretation of social cues is a crucial ability for everyday life. While processing socially relevant information, beyond the low-level physical features of the stimuli to emotional information is known to influence human cognition in various stages, from early perception to later high-level cognition, such as working memory (WM). However, it remains unclear how the influence of each type of emotional information on cognitive processes changes in response to what has occurred in the processing stage. Past studies have largely adopted face stimuli to address this type of research question, but we used a unique class of socially relevant motion stimuli, called biological motion (BM), which depicts various human actions and emotions with moving dots to exhibit the effects of anger, happiness, and neutral emotion on task performance in perceptual and working memory. In this study, participants determined whether two BM stimuli, sequentially presented with a delay between them (WM task) or one immediately after the other (perceptual task), were identical. The perceptual task showed that discrimination accuracies for emotional stimuli (i.e., angry and happy) were lower than those for neutral stimuli, implying that emotional information has a negative impact on early perceptual processes. Alternatively, the results of the WM task showed that the accuracy drop as the interstimulus interval increased was actually lower in emotional BM conditions than in the neutral condition, which suggests that emotional information benefited maintenance. Moreover, anger and happiness had distinct impacts on the performance of perception and WM. Our findings have significance as we provide evidence for the interaction of type of emotion and information-processing stage.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.226-229
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• 2014

편측무시는 뇌졸중 환자에게서 나타나는 지각 손상중의 하나로 말초 운동 및 감각 신경의 손상과 상관없이 손상된 대뇌반구의 반대편의 공간과 신체의 지각이 감소된 상태로 양방향에서 동시에 주어지는 자극에 대해서 한쪽 자극만을 지각하며 뇌손상 반대편의 신체 움직임의 인식 부족과, 무시된 공간쪽으로의 적은 눈 움직임을 보인다. 이와 같은 편측무시를 측정하는 기존 방법으로는 Albert Test, Line bisection Test, Star Cancellation Test 등이 있다. 하지만, 기존 편측무시 평가 방식에는 여러 가지 단점들이 발생한다. 항상 새로운 평가용지가 필요, 검사시간이 오래 소모되고, 모든 작업을 수작업으로 진행, 종이로 데이터를 관리, 수작업이므로 인력낭비 발생한다. 따라서 본 논문에서는 이러한 아날로그 방식에서 나오는 문제점들을 누구나 사용하고 있는 스마트 디바이스를 이용해 디지털방식으로 전환하여 기존의 비효율적이던 방식을 개선시키고자 평가시스템을 개발하고자 한다.

• Journal of Oral Medicine and Pain
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• v.30 no.4
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• pp.465-473
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• 2005

The purpose of this study was to evaluate the desensitizing effects of a Nd:YAG laser (Sunlase, SUNRISE Technologies, Inc., USA) irradiation on cervically exposed hypersensitive dentine. 45 patients was irradiated with pulsed Nd:YAG laser (1.5 W, 20 Hz, 75 mJ/pulse, 4 minutes) as the experimental group, 27 patients was mock irradiated as the control group. The degree of sensitivity to the thermal and tactile stimuli were determined qualitatively with an evaporative stimulus defined as two times air blast at a distance of 3 mm from each site to be tested and with a mechanical stimulus as a slightly scratching the cervical site with a dental explorer. A qualitative registration of the degree of discomfort was determined according to a numerical pain scale(NPS) in an 11-point scale in which 0= "no pain" and 10="most excruciating pain imaginable". Recordings were assessed before treatment, immediately after, 1 and 2 weeks after treatment. Pain tolerance threshold and pulp vitality were evaluated with electric pulp tester before and immediately after treatment. 1. Desensitizing of hypersensitive dentine with Nd:YAG laser irradiation was more effective than that with mock irradiation. 2. The placebo effect of mock irradiation was recognized for severe sensitive teeth($NPS\;{\geqq}\;6$), but not for moderate sensitive teeth(NPS < 6). 3. Laser irradiation did not affect the pain tolerance threshold and pulp vitality of the hypersensitive teeth. 4. Desensitizing effect of laser irradiation for the hypersensitive teeth had been continuing at least 2 weeks. It was concluded that desensitizing of hypersensitive dentine with a Nd:YAG laser is effective and the maintenance of the positive result was more prolonged than the placebo effect.