Prefrontal cortical hemodynamics and functional network organization during Tai Chi standing meditation: an fNIRS study

During Tai Chi standing meditation (Zhan Zhuang), experienced male practitioners showed significantly higher oxygenated hemoglobin concentrations in the bilateral dorsolateral prefrontal cortex, ventrolateral prefrontal cortex, frontal eye field, and pre-motor cortex compared to standing rest. Deoxygenated hemoglobin decreased in the left ventrolateral prefrontal cortex and right pre-motor cortex and dorsolateral prefrontal cortex. Functional connectivity between left and right prefrontal cortex strengthened, and the brain's functional networks displayed small-world architecture with more network hubs in the dorsolateral and ventrolateral prefrontal cortex during meditation. These changes indicate that Tai Chi standing meditation alters cortical blood flow and brain functional network organization.

Study at a glance

Abstract

Introduction Tai Chi standing meditation (Zhan Zhuang, also called pile standing) is characterized by meditation, deep breathing, and mental focus based on theories of traditional Chinese medicine. The purpose of the present study was to explore prefrontal cortical hemodynamics and the functional network organization associated with Tai Chi standing meditation by using functional near-infrared spectroscopy (fNIRS). Methods Twenty-four channel fNIRS signals were recorded from 24 male Tai Chi Quan practitioners (54.71 ± 8.04 years) while standing at rest and standing during Tai Chi meditation. The general linear model and the SPM method were used to analyze the fNIRS signals. Pearson correlation was calculated to determine the functional connectivity between the prefrontal cortical sub-regions. The small world properties of the FC networks were then further analyzed based on graph theory. Results During Tai Chi standing meditation, significantly higher concentrations of oxygenated hemoglobin were observed in bilateral dorsolateral prefrontal cortex (DLPFC), ventrolateral prefrontal cortex (VLPFC), frontal eye field (FEF), and pre-motor cortex (PMC) compared with the values measured during standing rest ( p < 0.05). Simultaneously, significant decreases in deoxygenated hemoglobin concentration were observed in left VLPFC, right PMC and DLPFC during Tai Chi standing meditation than during standing rest ( p < 0.05). Functional connectivity between the left and right PFC was also significantly stronger during the Tai Chi standing meditation ( p < 0.05). The functional brain networks exhibited small-world architecture, and more network hubs located in DLPFC and VLPFC were identified during Tai Chi standing meditation than during standing rest. Discussion These findings suggest that Tai Chi standing meditation introduces significant changes in the cortical blood flow and the brain functional network organization.