Effects of progressive muscle relaxation on cerebral activity: An fMRI investigation.

OBJECTIVES Progressive muscle relaxation (PMR) is one of the self-management relaxation techniques that can be used in the general population and patients with specific issues. However, no study to date has revealed the brain activity associated with PMR. Therefore, we assessed the changes in brain activity induced by PMR using functional magnetic resonance imaging (fMRI). DESIGN AND SETTING We conducted an intervention study with PMR and control sessions. The subjects were twelve healthy adult men who had no prior experience of PMR. INTERVENTIONS Subjects performed a control session in which muscles were repeatedly simply tensed and relaxed. Subsequently, a PMR session took place, during which muscle tension was reduced through a systematic procedure of tensing and relaxing of muscle groups combined with structured breathing. MAIN OUTCOME MEASURES We identified and visualised brain activity based on individual and group-level analysis of fMRI data. RESULTS Eleven subjects' data were analysed. In the control session, brain activity broadly changed, while the change was limited to specific parts of the cerebral cortex and limbic system in the PMR session. PMR gradually decreased activity in the superior frontal gyrus (SFG), inferior frontal gyrus (IFG), and posterior cingulate cortex (PCC). In a region of interest (ROI) analysis, interactions between sessions were observed in the putamen, anterior cingulate cortex (ACC), postcentral gyrus (PCG), and insula. CONCLUSIONS That PMR led to few areas showing changed activity suggests that the technique may suppress brain activity. Even novices may be able to induce such a focused mental state.