Modeling the information pathways in human brain during motor task with concurrent visual stimulation

Abstract

Recently, the increasing interest in the determination of directional connectivity in brain is observed. The determination is crucial to understand the mechanisms of the information processes in brain. Method based on the estimation of correlation/ coherence functions between the activities of pairs of simultaneously analyzed structures have been the most popular approaches. In previous study, the application of coherence function has been applied to investigate the effects of external visual stimulation on cortico-muscular synchronization. It was proven that regions with enhanced 8-12 Hz (alpha)/decreased 31- 50 Hz (gamma) power have strong coupling between them and demonstrated as codes of brain functional activity. In this project, further study has been done to provide the reliable information pathways/ direction between the regions of the brain by adopting partial directed coherence method. The method has been applied in two tasks, i.e. Control task and Count Visual Stimuli task. The Control task required the subject to maintain first dorsal interosseous muscle contraction without visual stimulation. In Count Visual Stimuli task, the subject was asked to count certain stimuli in a random series of visual stimuli displayed on a screen while maintained the muscle contraction. The result showed that in control task, most of the sources of the information pathways were from the frontal lobe due to the muscle contraction. In count visual stimuli task, most of the sources of the information pathways came from the occipital, temporal and parietal lobe due to the visual interpretation processes. As conclusion, partial directed method provides the information pathways / direction in human brain during motor task with concurrent visual stimulation.