Analysis of EEG changes between the frontal and occipital cortex during speech.

A method of spatiotemporal analysis, using time series analysis techniques to represent activity in multiple brain regions, was applied to the interpretation of EEG information changes between the frontal and occipital areas during speech. This paper proposes and discusses a bidirectional communication model between the frontal and occipital cortices. Entropy analysis was introduced and used to simplify the calculation of transinformation in two dimensions. In this work, transinformation with direction between the frontal and occipital cortices before and during speech was investigated quantitatively for 11 subjects. The dominant information flow in the occipital-frontal direction was found immediately before speech in the right hemisphere. During speech, the dominant information flow was found in the occipital-frontal direction in both the right and left hemispheres. These results suggest that the method used in our work is feasible to analyze EEG signals in language processes.