Central and autonomic nervous system interaction is altered by short-term meditation

Abstract

Five days of integrative body-mind training (IBMT) improves attention and self-regulation in comparison with the same amount of relaxation training. This paper explores the underlying mechanisms of this finding. We measured the physiological and brain changes at rest before, during, and after 5 days of IBMT and relaxation training. During and after training, the IBMT group showed significantly better physiological reactions in heart rate, respiratory amplitude and rate, and skin conductance response (SCR) than the relaxation control. Differences in heart rate variability (HRV) and EEG power suggested greater involvement of the autonomic nervous system (ANS) in the IBMT group during and after training. Imaging data demonstrated stronger subgenual and adjacent ventral anterior cingulate cortex (ACC) activity in the IBMT group. Frontal midline ACC theta was correlated with high-frequency HRV, suggesting control by the ACC over parasympathetic activity. These results indicate that after 5 days of training, the IBMT group shows better regulation of the ANS by a ventral midfrontal brain system than does the relaxation group. This changed state probably reflects training in the coordination of body and mind given in the IBMT but not in the control group. These results could be useful in the design of further specific interventions.

Conflict of interest statement

Conflict of interest: The authors declare no conflict of interest.

Figures

Fig. 1.

Physiological indexes comparison for IBMT and relaxation training (RT). (A) Skin conductance response (SCR) before, during, and after training in the experimental (IBMT) and control (RT) groups. For SCR, the lower score shows more parasympathetic activity. (B) High-frequency HRV before, during, and after training in the experimental (IBMT) and control (RT) groups. For high-frequency HRV, the higher score shows more parasympathetic activity. (A and B) The horizontal axis indicates the 5 training stages: baseline before training, 3 periods of IBMT or RT with 9 min each (1, 2, 3), and baseline after training. The vertical axis indicates SCR change and percentage of change in normalized units of high-frequency (nuHF) HRV, respectively. *, P < 0.05; ns, no significance.

Fig. 2.

Comparison maps of r-CBF change in IBMT compared to RT in left and right hemispheres after training minus before training. The upper row is the left hemisphere and the lower row the right hemisphere. Left, a medial view; right, a lateral view (displayed at PFWE < 0.05, corrected).

Fig. 3.

Comparison maps of r-CBF change in RT compared to IBMT in left and right hemisphere after training minus before training. The upper row is the left hemisphere and the lower row the right hemisphere. Left, a medial view; right, a lateral view (displayed at PFWE < 0.05, corrected).

Fig. 4.

Correlation between high-frequency HRV and FCz-theta in IBMT following 5 days of training. The horizontal axis indicates the percentage of change in frontal midline theta power (in FCz) and the vertical axis indicates the percentage of change in normalized units of high-frequency (nuHF) HRV. A positive Pearson's correlation was observed (r = 0.551, P = 0.033).