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Brain activity during motor task with concurrent visual stimulation

Ali, Siti Hajar Aminah and Mat Safri, Norlaili and W. M. Ridzwan, W. M. Fatihilkama (2011) Brain activity during motor task with concurrent visual stimulation. Elektrika: journal of electrical engineering, 13 (1). pp. 7-12. ISSN 01284428

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Previously, the effects of external visual stimulation on cortico-muscular synchronization was studied and it was found that enhanced 8-12 Hz (alpha)/decreased 31-50 Hz (gamma) oscillations in the brain affect strength of the 13-30 Hz oscillation of cortico-muscular synchronization. In this paper, we study whether the 8-12 Hz enhancement/31-50 Hz decrement in the various brain regions are coupled together or not using cortico-cortical coherence analysis. The brain signals (EEG) and the muscle signal (EMG) were recorded from ten normal subjects during two tasks, i.e. Control and Visual (Ignore or Count) tasks. The Control task required the subject to maintain first dorsal interosseous muscle contraction without visual stimulation. In the Visual task, a random series of visual stimuli were displayed on a screen while the subjects maintained the muscle contraction. The subjects were asked to ignore the stimuli in the Ignore condition and to count certain stimuli in the Count condition. Increased coupling was found at the 8-12 Hz oscillation between various scalp locations during both Visual conditions with more EEG coupling exist in the Count condition when compared with the Control task. Despite the attenuation of 31-50 Hz oscillation in the brain, strong EEG coupling at the frequency band was found between C3 and O2 sites and between right and left temporal area for the Ignore condition when compared to the Control task. None was found for the Count condition. At low frequency band (1-3 Hz (delta) and 4-7 Hz (theta)), increased EEG coupling was found between sites in posterior area, and between posterior and frontal area for both Visual conditions when compared to Control task. However, a decrease in inter-hemispheric interaction was found for Ignore condition at the low frequency oscillation. The present results show that regions with enhanced/decreased power have strong coupling between them and demonstrated as codes of brain functional activity.

Item Type:Article
Uncontrolled Keywords:EEG coupling, coherence, electroencephalogram, electromyogram
Subjects:T Technology > TK Electrical engineering. Electronics Nuclear engineering
Divisions:Electrical Engineering
ID Code:22753
Deposited By: Mrs Liza Porijo
Deposited On:14 Jul 2014 03:19
Last Modified:08 Feb 2017 04:42

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