Cerebral blood flow effects of yoga training: preliminary evaluation of 4 cases

Abstract

Objectives: Experienced practitioners of yoga have been shown to alter brain function, but this case series measured cerebral blood flow before and after a 12-week training program in Iyengar yoga (IY) for naïve subjects.

Methods: On the first day, each of the 4 subjects listened to the teacher speaking on the history and background of the yoga program while they were injected with 250 MBq of (99m)Tc-bicisate and received a single photon emission computed tomography scan (pre-program baseline). Subjects then had their first IY training and were injected and scanned with 925 MBq bicisate while they did their first meditation (pre-program meditation). Subjects then underwent a 12-week training program in IY and then underwent the same imaging protocol with a postprogram baseline and postprogram meditation scan. Baseline and meditation scans, before and after training, were compared using paired t tests.

Results: There were significant decreases (p < 0.05) between the pre- and postprogram baseline scans in the right amygdala, dorsal medial cortex, and sensorimotor area. There was a significant difference (p < 0.05) in the pre- and postprogram percentage change (i.e., activation) in the right dorsal medial frontal lobe, prefrontal cortex, and right sensorimotor cortex.

Conclusions: These initial findings suggest the brain experiences a "training effect" after 12 weeks of IY training.

Figures

FIG. 1.

This figure shows transaxial slices of the preprogram baseline state (A), the preprogram meditation state (B), the postprogram baseline state (C), and the postprogram meditation state (D). Cerebral blood flow (CBF) is represented as red > yellow > green > blue. These images show substantially greater CBF in the right prefrontal cortex (arrow) in the postprogram meditation scan compared to the activity in the baseline or the preprogram meditation scans. This suggests a training effect that enhances the activation in the prefrontal cortex after the yoga program.