Activation of the anterior prefrontal cortex and serotonergic system is associated with improvements in mood and EEG changes induced by Zen meditation

Abstract: To gain insight to the
neurophysiological mechanisms involved in Zen meditation, we evaluated the
effects of focused attention (FA) on breathing movements in the lower abdomen
(Tanden) in novices. We investigated hemodynamic changes in the prefrontal
cortex (PFC), an attention-related brain region, using 24-channel near-infrared
spectroscopy during a 20-minute session of FA on Tanden breathing in 15 healthy
volunteers. We found that the level of oxygenated hemoglobin in the anterior
PFC was significantly increased during FA on Tanden breathing, accompanied by a
reduction in feelings of negative mood compared to before the meditation
session. Electroencephalogra phy (EEG) revealed increased alpha band activity and
decreased theta band activity during and after FA on Tanden breathing. EEG
changes were correlated with a significant increase in whole blood serotonin
(5-HT) levels. These results suggest that activation of the anterior PFC and
5-HT system may be responsible for the improvement of negative mood and EEG
signal changes observed during FA on Tanden breathing.