• The Journal of Korean Physical Therapy
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• v.32 no.6
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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.

• Science of Emotion and Sensibility
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• v.19 no.1
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• pp.31-38
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• 2016

The brain and muscles both of which are composed of top-down structure occur the connectivity with the change of Electroencephalogram(EEG) and Electromyogram(EMG). In this paper, we studied the difference of functional connectivity between brain and muscles that by applying coherence method to EEG and EMG signals when users exercised upper limb with and without the movement intention. The changes in the EEG and EMG signals were inspected using coherence method. During the upper limb exercise, the mu (8~14 Hz) and beta (15~30 Hz) rhythms of the EEG signal at the motor cortex area are activated. And then the beta and piper (30~60 Hz) rhythms of the EMG signal are activated as well. The result of coherence analysis between EEG and EMG showed the coefficient of active exercise including movement intention is significantly higher than passive exercise. The coherence relations between cognitive response and muscle movement could interpret that the connectivity between the brain and muscle appear during active exercise with movement intention. The feature of coherence between brain and muscles by the status of movement intention will be useful in designing the rehabilitation system requiring feedback depending on the users' movement intention status.

• Korean Journal of Biological Psychiatry
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• v.18 no.1
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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.

• Science of Emotion and Sensibility
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• v.17 no.4
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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.

• Science of Emotion and Sensibility
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• v.13 no.1
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• pp.121-128
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• 2010

This study is to analyze change of connectivity between brain positions caused by relaxation through EEG coherence. EEG spectrum analysis method has been used to analyze brain activity when relaxation was experienced. However, the spectrum analysis method has a limit that could not observe interactive reaction between brain-functional positions. Therefore, coherence between positions was analyzed to observe connectivity between the measurement positions in this study. Through the method, the reaction of the central nervous system caused by the emotion change was observed. Twenty-four undergraduates of both genders(12 males and 12 females) were asked to close their eyes and listen to the sound. During experiment, EEG was measured at eight positions. The eight positions were F3, F4, T3, T4, P3, P4, O1, and O2 in accordance with International 10-20 system. The sounds with white noise and without were used for relaxation experience. Subjective emotion was measured to verify whether or not they felt relaxation. Subjective emotion of participants were analyzed by ANOVA method(Analysis of Variance). In the result, it was proved that relaxation was subjectively evoked when participants heard sound. Accordingly, it was proved that relaxation could be enhanced by the mixed white noise. EEG coherence between the measurement positions was analyzed. T-test was performed to find its significant difference between relaxation and not-relaxation. In the results of EEG coherence, connectivity with occipital lobes has been increased with relaxation, and connectivity with parietal lobes has been increased with non-relaxed state. Therefore, brain connectivity has shown different pattern between relaxed emotion and non-relaxed emotion.

• Korean Journal of Biological Psychiatry
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• v.12 no.2
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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.

• Proceedings of the KOSOMBE Conference
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• v.1992 no.11
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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.

• Journal of IKEEE
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• v.22 no.4
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• pp.1109-1114
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• 2018

Electroencephalogram (EEG) is a tool used to study brain activity caused by external stimuli. In this process, artifacts are mixed and it is easy to distort the signal, so post-processing is necessary to remove it. Independent Component Analysis (ICA) is a widely used method for removing artifact. This method has a disadvantage in that it has excellent performance but some loss of brain wave information. In this paper, we propose a method to reduce EEG information loss by restricting the filter coverage using eye blink information obtained from Eyetracker. We then compared the results of the proposed method with the conventional method using quantization methods such as Signal to Noise Ratio (SNR) and Spectral Coherence (SC).

• Journal of Korean Physical Therapy Science
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• v.15 no.3
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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.

• Physical Therapy Korea
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• v.15 no.4
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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.