• The Journal of Korean Physical Therapy
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• 제32권6호
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• pp.365-371
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• 2020

Objective: To investigate the action observation effects of functional electrical stimulation (FES) on the communication between motor cortex and muscle through corticomuscular coherence (CMC) analysis. Methods: Electroencephalogram (EEG) and electromyogram (EMG) of 27 healthy, nonathlete subjects were measured during action observation, FES, and action observation with FES, which lasted for 7sper session for 10 times. All trials were repeated for 30 times. Simultaneously measured EEG raw data and rectified EMG signals were used to calculate CMC. Only confidence limit values above 0.0306 were used for analysis. CMC was divided into three frequency domains, andthe grand average coherence and peak coherence were computed. Repeated ANOVA was performed to analyze the coherence value difference for each condition's frequency band. Results: CMC showed significant differences in peak coherence and average coherence between the conditions (p<0.05). Action observation application with FES in all frequency band showed the highest peak and average coherence value. Conclusions: The results of this study are assumed to be the combination of increased eccentric information transfer from the sensorymotor cortex by action observation and an increased in concentric sensory input from the peripheral by the FES, suggesting that these are reflecting the sensorimotor integration process.

• 감성과학
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• 제19권1호
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• pp.31-38
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• 2016

뇌와 근육은 상의 하달식 구조로 상지 운동 수행 과정에서 뇌파와 근전도 신호의 변화와 함께 기능적 연결성이 발생한다. 본 논문에서는 사용자가 상지 운동을 수행하였을 때의 뇌파와 근전도 신호에 대해 코히어런스 방법을 적용하여 운동 의도 여부에 따른 뇌와 근육간의 연결성 차이를 규명하고자 한다. 상지 운동을 수행하는 과정에서 운동 피질 영역의 뇌파는 뮤 리듬(mu rhythm, 8~14 Hz)과 베타 리듬(beta rhythm, 15~30 Hz)에서 활성화 되며, 근전도 신호는 베타 리듬과 파이퍼 리듬(piper rhythm, 30~60 Hz)에서 활성화 된다. 뇌파와 근전도 신호간의 코히어런스 분석 결과 운동 의도를 포함한 능동 운동 수행 시 수동 운동을 수행하였을 때 보다 유의미한 차이로 높은 코히어런스 계수가 확인되었다. 이는 인지적 반응과 근육의 움직임 사이의 코히어런스 관계로 운동 의도가 포함된 상지 운동 수행 과정에서의 뇌와 근육간의 연결성을 해석할 수 있었다. 운동 의도에 따른 뇌-근육간의 코히어런스 특징을 이용한다면 재활기기 사용자의 운동 의도에 따라 피드백이 필요한 재활 훈련 시스템 설계에 도움이 될 수 있을 것으로 사료된다.

• 생물정신의학
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• 제18권1호
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• pp.25-35
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• 2011

Objectives : Cerebral laterality is thought to be an important marker for neurodevelopment. Prenatal testosterone could influence both cerebral laterality and 2nd to 4th finger length ratio(2D : 4D). EEG coherence and 2D : 4D were examined to investigate the relationship between prenatal testosterone level and cerebral laterality. Methods : EEG was recorded in 24 healthy subjects in the eyes closed resting state. Differences in 2D : 4D finger ratio were used to discriminate "masculine finger type" and "feminine finger type" groups. The 2D : 4D ratio was lower and greater than one for the "masculine finger type" group and "feminine finger type" group, respectively. We used coherence analysis to estimate the cortical functional connectivity. Results : There were statistically meaningful relationships among cerebral functional connectivity, sex and finger ratio. Man and masculine finger type group showed higher intra-hemispheric coherence than those of woman and feminine finger type group. Woman and feminine finger type group showed higher inter-hemispheric coherence than those of man and masculine finger type group. Conclusions : These results imply that prenatal testosterone might act as important determinants of cerebral laterality. Further examination of the relationship between 2D : 4D and EEG coherence in schizophrenia could give some clues for the neurodevelopmental hypothesis of schizophrenia genesis.

• 감성과학
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• 제17권4호
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• pp.51-60
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• 2014

This double-blind study, as a human experiment of nonlocality, investigated the effects of senders' intention on the central nervous system of a distant human receiver and it explored the roles that motivation might have in modulating these effects. Whole brain activity was measured in the receiver whom was asked to relax in a distant room for 16 minutes; the sending person directed intention of oneness toward the receiver during repeated variable-second epochs separated by variable-second non-intention epochs. The total length of intention epochs and that of nonintention epochs were balanced. Eighteen sessions were conducted. In 9 of those sessions, the sender was the receiver's lover. In another 9 of those sessions, the sender was just acquainted with the receiver before the session. The receiver's whole brain activity recorded during the intention epochs were compared with the same measures recorded during the nonintention epochs used as controls. The statistical difference between the intentions versus controls across 18 sessions was examined by paired-t test. In addition, subgroup analysis for the 9 couple sessions and 9 non-couple sessions were additionally examined by the same test. The effect of distant intentionality decreased slow waves or increased EEG fast waves mainly in frontal regions, and increased EEG coherence during the intention epochs. The effects was not statistically significant after Bonferroni correction, but the couple sessions combined showed the largest effect followed by all sessions combined. Non-couple sessions combined showed the smallest effect. The changes in EEG power mean that receiver participants became more alert during the intention epochs and the change in EEG coherence might be evidence of coherent heart influence on EEG activity. Planned comparison with specific hypothesis testing for the suggested changes in this study have to be followed for an evidence of electroencephalographic changes in isolated subjects for the distant mental intention.

• 감성과학
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• 제13권1호
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• pp.121-128
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• 2010

본 연구는 이완에 따른 뇌 영역간의 연결성을 코히런스 분석방법으로 확인하고자 한다. 기존의 이완유발에 따른 뇌 활동 변화는 EEG 스펙트럼 분석방법을 사용하여왔다. 하지만 스펙트럼 분석방법으로는 측정영역에서의 반응만을 관찰할 수 있고, 뇌 영역간의 연결성을 분석하기는 힘들다. 따라서 측정점 사이의 연결성을 관찰할 수 있는 코히런스 분석방법으로 이완에 따른 뇌 영역 간의 연결성을 확인하였다. 이를 통해 감성 변화에 따른 중추신경계의 변화를 관찰할 수 있었다. 실험은 24명의 대학생을 대상으로 눈을 감고 이완음향을 듣도록 지시하고 8개의 위치에서 EEG를 측정하였다. EEG측정위치는 국제적인 10-20법에 의거한 F3, F4, T3, T4, P3, P4, O1, 그리고 O2지점을 사용하였다. 실험에 사용된 음향은 White noise를 혼합한 음향과 혼합하지 않은 음향을 사용하였다. 그리고 실제로 이완이 되었는지 확인하기 위해 주관적 감성을 함께 측정하였다. 주관적 감성 응답은 ANOVA(Analysis of Variance)하였다. 음향을 들었을 때 실제로 이완효과가 발생하며, White noise가 이완을 증가시키는 것을 확인하였다. EEG는 측정영역 사이의 코히런스를 측정하였다. 그리고 White noise를 혼합한 음향과 혼합하지 않은 음향을 들었을 때의 코히런스 결과를 t-test하여 유의성을 확인하였다. 분석결과 White noise를 혼합한 음향에서 후두엽과의 연결성이 증가하였고, White noise를 혼합하지 않은 음향에서는 두정엽과의 연결성이 증가하는 결과를 확인하였다. 이를 통해 이완일 때의 뇌 기능 연결성의 변화를 관찰할 수 있는 중요한 결과를 도출하였다.

• 생물정신의학
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• 제12권2호
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• pp.123-135
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• 2005

Objectives:EEG coherence could imply the connectivity between two different areas of the brain, which is known to be important in the pathophysiology of bipolar I disorder(BPD I) and schizophrenia. The authors investigated EEG coherence in patients with BPD I and schizophrenia to examine the connectivity of the neural circuit. Methods:EEGs were recorded in 15 schizophrenia and 14 bipolar disorder patients, and 14 age-matched normal control subjects from 16 electrodes with linked-ear reference. Spectral parameters and coherence were calculated for the alpha bandwidth(8-13Hz) by a multi-channel autoregressive model using 20 artifact-free 2-seconds epochs and the differences were compared among three groups by two different statistical methods;F-test and Kruskal-Wallis test. Furthermore, when there were significant differences among three groups, Scheffe's multiple comparison tests were provided and Jonckheere-Terpstra tests for the ordered alternative were given. Results:In the intra-hemispheric comparison, left frontal coherence was increased in order of control, BPD I and schizophrenia. In the inter-hemispheric comparison, 1) inter-prefrontal coherence in BPD I was signifi- cantly higher than in normal controls, and 2) inter-prefrontal coherence in schizophrenia was significantly lower than in controls. Conclusion:These results suggest that 1) both schizophrenia and BPD I are diseases having the abnormality of neural circuit connectivity in both frontal and prefrontal lobes, and 2) the abnormality is more severe in schizophrenia than in BPD I. Furthermore, the data support that a common pathogenetic process may reside in both schizophrenia and BPD I.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1992년도 추계학술대회
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• pp.77-78
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• 1992

In this study, the PSD and coherence spectra of electroencephalogram are estimated us ins multichannel AR model. This enables us to perform the topographic mapping of EEG by interpolation.

• 전기전자학회논문지
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• 제22권4호
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• pp.1109-1114
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• 2018

뇌파(Electroencephalogram, EEG)는 외부 자극 때문에 발생하는 뇌 활동을 연구하기 위해 사용되는 도구로 두피에 전극을 부착하여 기록한다. 이 과정에서 잡파(artifact)가 혼입되어 신호를 왜곡시키기 쉬워 이를 제거하기 위한 후처리가 필수적이다. 잡파 제거를 위해 널리 사용되는 방법으로 독립성분분석(Independent Component Analysis, ICA)이 존재한다. 이 방법은 성능은 우수하나 뇌파 정보를 일부 손실시키는 단점이 있다. 본 논문에서는 이러한 문제점을 보완하기 위해 시선 추적 센서(Eyetracker)를 통해 얻은 눈 깜빡임 정보를 이용하여 필터 적용 범위를 제한함으로써 뇌파 정보 손실을 줄이는 방법을 제안한다. 이후 신호 대 잡음 비(Signal to Noise Ratio, SNR), 스펙트럼 일관성(Spectral Coherence, SC) 등의 정량화 방법을 이용하여 기존의 방법과 제안하는 방법의 결과를 비교하였다.

• 대한물리치료과학회지
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• 제15권3호
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• pp.9-17
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• 2008

Background : The conventional electroencephalography(EEG) is commonly used as aid in the diagnosis of dementia. Recently developed quantitative electroencephalography(qEEG) provides data that are not achievable by conventional EEG. The aim of this study was to find out the usefulness of quantified-EEG in dementia. Method : Twenty elderly women(10 normal elderly, 10 demented elderly) were participated in this study. EEG power and coherence was computed over 21 channels; right and left frontal, central, parietal, temporal and occipital areas. Result : The activity of ${\alpha}$ wave was more higher than others significantly at frontal and parietal areas in normal elderly, but the activity of ${\theta}$ wave was higher in demented elderly. And the activity of ${\theta}$ wave in demented elderly women was more higher than normal elderly women significantly. Conclusion : In conclusion, we discovered that quantitative EEG was used to diagnose dementia.

• 한국전문물리치료학회지
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• 제15권4호
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• pp.70-79
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• 2008

The purpose of this study was to find out the effects of electroencephalograph (EEG) power and coherence on cognitive function in normal elderly, non-demented elderly with mild cognitive impairment, and demented elderly during working cognition tasks. Forty elderly women (19 demented elderly, 10 non-demented elderly with mild cognitive impairment, 11 norma1 elderly) participated in this study, All subjects performed working cognition tasks with Raven's CPM while EEG signal was recorded, EEGs were measured continuously at rest and during the working cognition task. EEG power and coherence was computed over 21 channels: right and left frontal, central, parietal, temporal and occipital region. We found that there were more correct answers among normal elderly women than in other groups Owing the working cognition task, ${\Theta}$ wave at Fp1, Fp2 and F8, a wave at Fp2, ${\beta}$ wave at Fp1, Fp2. F4 and F8 of the frontal region was increased significantly in the demented elderly group. On the other hand. ${\Theta}$ wave at Fp1, Fp2 and F7, ${\beta}$ wave at Fp1, Fp2, F3 and F7 of the frontal region was increased significantly in the group of non-demented elderly with mild cognitive impairment. In contrast. in the normal elderly group, all of the ${\Theta}$ wave and ${\beta}$ wave at Fp1, Fp2, F3, F4, F7 and F8 of the frontal region (except ${\beta}$ wave at F3) was increased significantly, These results suggest that the nerves in prefrontal and right hemisphere regions were most active in the demented elderly group during problem solving, and the nerves in the prefrontal and left hemisphere lobe were most active in the group of non-demented elderly with mild cognitive impairment. In contrast, me majority of nerves in the frontal region were active in the normal elderly group.