Topographic analysis of human EEG during voluntary abdominal breathing

Abstract

We previously examined the effect of voluntary abdominal breathing (VAB) related to Zen Meditation on EEG, and found that the spectral power in high-frequency alpha band (10-13Hz) increased during the eyes-open condition as well as the eyes-closed condition. Because the urinary 5-HT level after the VAB increased, we hypothesized that the activity of the 5-HT neuron located in the brain stem may be involved in modulating the EEG power during VAB. In the present study, we performed topographic analysis of the EEG power during VAB in an eyes-closed condition by using a brain mapping technique. Although the spectral power of low-frequency alpha band (8-10Hz) appeared over the occipital and the parietal area promptly after closing the eyes, it gradually decreased during VAB. The high-frequency alpha power began to increase ~5 minutes after VAB and its topographic distribution extended from the occipital to the central area. It further extended from the occipital to the frontal area 10 minutes after VAB; this extended distribution was sustained until the completion of VAB. The urinary and/or blood 5-HT levels tended to increase after VAB. These results support our hypothesis that the activity of 5-HT neurons located in the brain stem may be involved in modulating the EEG power during VAB. [Jpn J Physiol 54 Suppl:S208 (2004)]