• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2009.05a
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• pp.141-144
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• 2009

본 연구는 사상관련전위를 이용하여 의식하에 제시된 미적자극이 대뇌활동에 미치는 영향을 밝혀내고자 이루어졌다. 이를 위해, 16명의 실험참가자에게 masking법를 이용해 미적자극을 의식하에 제시하였다(10msec). 제시된 자극은 선행연구를 통해 선정된 Beautiful Images(미자극), Ugly Images(추자극), Neutral Images(중성자극)이였다. 사상관련전위(event-related potentials; ERPs)는 64채널의 뇌파계를 이용하여 측정하였다. 그 결과, 후두엽 (Oz) 및 좌측두엽 (T5)에서 미자극에 의해 나타난 ERPs초기성분인 P1, N1, P2, N2의 진폭이 중성자극에 의해 나타난 진폭보다 컸다. 그리고, 후두염에서 추자극에 의해 보여진 P2, N2의 진폭 및 Late Slow Wave(LSW)의 평균전위가 중성자극에 의해 보여진 것보다 컸다. 이와 같은 ERPs성분은 자극의 탐지, 패턴인지, 기억탐색, 표적선택 등과 같은 자극의 정보처리와 관련되어 있다고 보고되고 있다. 따라서, 의식하에 제시된 미적자극은 서로 다른 대뇌 활동을 일으킴을 알 수 있다. 이는 인간은 의식하에서 미적자극에 대한 정보처리를 하는 기능을 가지고 있음을 뜻한다.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.12 no.1
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• pp.25-50
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• 2001

Using Fourier transformation and wavelet analysis, we compared the auditory event-related potentials of the patients with attention deficit-hyperactivity disorders(abbr. ADHD, 13 boys) and normal control children(8 boys). Amplitudes of the event-related potentials which were calculated via Fourier transformation were compared between the groups and between conditions(non-target versus target) in each group. To the non-target stimuli, the patients with ADHD showed significantly greater amplitudes across almost all of the electrode sites and frequencies. To the target stimuli, the incidents which ADHD patients showed much higher amplitudes than normal controls significantly decreased, while those of the reverse results increased significantly. These results were consistent with the comparison results about negative difference wave(abbr. Nd wave) using Fourier transformation. In summary, it was proved that non-target stimulus which should be ignored elicited more robust electrical response from the patients with ADHD than normal children, but the target stimulus which reguired active processing did much less electrical activity in the patients. For the patients, they showed much inhibited electrical response to the target stimuli in some electrodes and frequency ranges. Normal children were more strongly stimulated by the target stimuli in almost all electrodes and frequency ranges than the patients, but less in prefrontal leads and frontal leads. Wavelet analysis results proved that early responses(0-300msec) to the nontarget stimuli of the patients were significantly greater than the normal controls in prefrontal, anterior frontal, some parts of temporal, and occipital lobes and that late response(300-370msec) were significantly lesser than normal children in parietal and central electrodes. Target stimuli elicited significantly higher electrical activity in both group than non-target stimuli did. Prefrontal and frontal lobes showed stronger responses in the patients than normal children irrespective of stimulus condition, but parietal and temporal lobes did higher activities in normal children than the patients only to the target stimuli. In conclusion, the patients with ADHD showed much greater responses to the stimuli which should be ignored, but failed to activated the necessary processes to the target stimuli. Also, we found that the frequency-dimension analysis and wavelet analysis were useful for the signal processing such as event related potentials.

• Journal of Biomedical Engineering Research
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• v.30 no.4
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• pp.306-310
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• 2009

The purpose of this study is to observe the change in gamma-band cortical activities (GBAs) due to task difficulty. Event-related potential and gamma-band activity were investigated using electroencephalograms recorded during auditory oddball tasks with two difficulty levels. For more difficult task, the amplitude of P300 decreased and the peak latency of P300 was delayed significantly compared to easier task. The induced GBA decreased considerably during the P300 latency period and the peak latency of the induced GBA was delayed for more difficult task. The results imply that the difficulty-related change in cortical information processing may be implemented as a change in the strength of local neuronal association.

• Korean Journal of Cognitive Science
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• v.27 no.3
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• pp.421-439
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• 2016

The present study investigates the effects of semantic transparency on the learning of new words using both behavioral measures and event-related brain potentials. Participants studied novel words with either semantically transparent or opaque definitions while their brain potentials were recorded. Learning performance was assessed with both a lexical decision task and a recall test. The results indicated that transparent novel words were easier to learn than opaque words. More specifically, self-paced learning times were shorter for transparent novel words across three study sessions. Transparent words also elicited reduced N400s compared with opaque words in all sessions. Moreover, lexical decisions to both learned novel words and real words were faster and more accurate within the transparent condition compared to the opaque condition. These results suggest that semantic transparency also plays an important role within word learning, just as within word recognition, further supporting the notion that morphological information is critical within lexical processing.

• Korean Journal of Biological Psychiatry
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• v.8 no.2
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• pp.251-257
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• 2001

Backgrounds : Gamma band oscillatory activity is considered to be related to cognitive functions and illustrates that the concept of event-related oscillations bridges the gap between single neurons and neural assemblies. An event-related gamma oscillation is the time-locked responses of specific frequency, and can be identified by computing the amplitude frequency characteristics of the averaged event-related potentials(ERPs) after stimulation. Objectives : We purposed to present experimental paradigm to investigate ${\gamma}$-band oscillation activities from the recording of ERPs by using auditory oddball paradigm and investigate the difference of ${\gamma}$-band activity between schizophrenia and normal controls. Methods : The ERPs resulting from auditory stimuli with oddball paradigm in a group of schizophrenics(n=11), and also a group of age-, sex-, and handedness matched normal controls, were recorded by 128 channel EEG. The ${\gamma}$-band oscillatory activities were calculated by using time-frequency wavelet decomposition of the signal between 20 and 80Hz. The ${\gamma}$-band oscillatory activities of both groups were compared by t-test. Results : The ${\gamma}$-band oscillatory of the leads Fz, Cz, and Pz of both groups were represented well in the time-frequency maps. Significant increases of the ${\gamma}$-band activity in normal controls compared with schizophrenics were observed around 160 msec, 350 msec, and 800 msec after stimulation. Conclusions : Our results suggested that the increment in ${\gamma}$-band oscillatory activity during cognitive operations and decreased ${\gamma}$-band activity in schizophrenics may be associated with the cognitive dysfunctions and the pathophysiology of the schizophrenia.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.8 no.2
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• pp.273-286
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• 1997

Objective：This study was designed to evaluate effects of methylphenidate(MPH) on event-related potentials(ERP) and continuous performance test(CPT) in attention-deficit hyperactivity disorder (ADHD) and to see the correlation between changes in ERP and changes in performance. Method：ERP and CPT were used to examine the acute effects of MPH(0.5mg/kg) in eleven ADHD boys(89-103 months old). Results：1) After MPH administration, P3 latency to nontarget stimuli at Fz was significantly decreased (p<0.01) and P2 amplitudes to target stimuli at Pz and at Oz and P3 amplitude to target stimuli at Cz were significantly increased(p<0.05). 2) Commission error and omission error in the CPT-X and commission error in the CPT-AX were decreased(p<0.01), and hits and perceptual sensitivity(d') in the CPT-X and d′ in the CPT-AX were increased(p<0.01). 3) The change of P3 latency to nontarget stimuli at Fz and the change of d′ in the CPT-X were negatively correlated(p<0.05), and the change of P2 amplitude to target stimuli at Pz and d′ in the CPT-AX were positively correlated(p<0.05). Conclusion：MPH improves change orienting reaction, the delivery of task relevant information, accuracy and perceptual sensitivity in ADHD. And the increase of ability to discriminate targets from non-targets reflects reduced evaluation time in large memory component task and enhanced change orienting reaction in simple task.

• Journal of Audiology & Otology
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• v.25 no.3
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• pp.163-170
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• 2021

Cortical deafness is a clinical rarity whereby a patient is unresponsive to all types of sounds despite the preserved integrity of the peripheral hearing organs. In this study, we present a patient who suddenly lost his hearing following ischaemic infarcts in both temporal lobes with no other neurological deficits. The CT confirmed damage to the primary auditory cortex (Heschl's gyrus) of both hemispheres. Initially, the patient was unresponsive to all sounds, however, he regained some of the auditory abilities during 10 months follow up. Pure tone threshold improvement from complete deafness to the level of moderate hearing loss in the right ear and severe in the left was observed in pure tone audiometry. Otoacoustic emissions, auditory brainstem responses, and acoustic reflex findings showed normal results. The middle and late latency potential results confirmed objectively the improvement of the patient's hearing, however, after 10 months still, they were somewhat compromised on both sides. In speech audiometry, there was no comprehension of spoken words neither at 3 nor at 10 months. The absent mismatch negativity confirmed above mentioned comprehension deficit. The extensive auditory electrophysiological testing presented in this study contributes to the understanding of the neural and functional changes in cortical deafness. It presents the evolution of changes after ischaemic cerebrovascular event expressed as auditory evoked potentials starting from short through middle and long latency and ending with event-related potentials and supported by neuroimaging.

• Korean Journal of Audiology
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• v.25 no.3
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• pp.163-170
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• 2021

Cortical deafness is a clinical rarity whereby a patient is unresponsive to all types of sounds despite the preserved integrity of the peripheral hearing organs. In this study, we present a patient who suddenly lost his hearing following ischaemic infarcts in both temporal lobes with no other neurological deficits. The CT confirmed damage to the primary auditory cortex (Heschl's gyrus) of both hemispheres. Initially, the patient was unresponsive to all sounds, however, he regained some of the auditory abilities during 10 months follow up. Pure tone threshold improvement from complete deafness to the level of moderate hearing loss in the right ear and severe in the left was observed in pure tone audiometry. Otoacoustic emissions, auditory brainstem responses, and acoustic reflex findings showed normal results. The middle and late latency potential results confirmed objectively the improvement of the patient's hearing, however, after 10 months still, they were somewhat compromised on both sides. In speech audiometry, there was no comprehension of spoken words neither at 3 nor at 10 months. The absent mismatch negativity confirmed above mentioned comprehension deficit. The extensive auditory electrophysiological testing presented in this study contributes to the understanding of the neural and functional changes in cortical deafness. It presents the evolution of changes after ischaemic cerebrovascular event expressed as auditory evoked potentials starting from short through middle and long latency and ending with event-related potentials and supported by neuroimaging.

• Korean Journal of Biological Psychiatry
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• v.19 no.3
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• pp.115-120
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• 2012

Objectives : Event-related potentials have been suggested as an objective marker for brain functions in psychiatric disorders. This study was aimed to investigate the relationships between P300, the mismatch negativity (MMN), the loudness dependence of the auditory evoked potential (LDAEP), demographic and clinical variables including neurocognitive abilities in patients with schizophrenia. Methods : P300, the MMN, and the LDAEP were measured and the Korean Stroop color-word test (K-stroop test) and the Wisconsin Card Sorting Test (WCST) were performed in 43 patients with schizophrenia. The relationship of the latency and amplitude of P300 and the MMN as well as regression slope of the LDAEP with demographic and clinical variables were analyzed by t-test and correlation analyses for categorical and continuous variables, respectively. Results : After controlling for age, the latency of central (Cz) and parietal (Pz) P300 posivitively correlated with GAF at admission (Cz ; ${\gamma}$ = 0.385, p = 0.047, Pz ; ${\gamma}$ = 0.421, p = 0.029). The amplitude of parietal P300 correlated with the correction rate of the K-stroop test (${\gamma}$ = 0.575, p = 0.002). In addition, the frontal (Fz) P300 latency tended to negatively correlated with the correction rate of the WCST (${\gamma}$ = -0.371, p = 0.057). Conclusions : Our findings suggest that the values of P300 latency and amplitude might be correlated with GAF at admission and working memory measured by the K-Stroop test and the WCST. Meanwhile, the MMN and the LDAEP did not correlate with demographic and clinical variables. These results support the results of previous studies showing associations with P300 and impaired cognitive ability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5003-5011
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• 2013

This paper measured whether neural and behavior responses to attention-emotion task were reflected to emotion regulation capacities. For this purpose, Nineteen healthy right-handed graduates participated in the emotion-attention task three times for three days. Before and after the negative and positive video clips were shown, the participants performed emotion-attention task. EEG and response time were recorded during emotion-attention task. There was positive correlation between ERP P100 and P300 component. The larger the P100 amplitudes at the specific positions, the longer the P300 latencies at these same positions during attention-emotion task. The longer the P300 latencies at the specific positions, the longer the delay in response time. Also, there is and individual differences in ERP components and response time during attention-emotion integration task. Individuals who had lower amplitude and shorter latency of ERP showed faster response time during attention-emotion task, regardless of the type of video clips. This characteristic was interpreted to the lower emotional controls due to premature response for target identification.