Experience of Meditation with Neuromodulation - 2 (EMN-2)

Mindfulness meditation (MM) is associated with modulation of EEG alpha activity, ECG (heart-rate variability [HRV]), and subjective experience. The current research attempts to further augment the physiological and subjective benefits of MM through concurrent alpha transcranial alternating current stimulation (alpha-tACS). Pre-post EEG and ECG-HRV, alongside self-report measures of meditative breath attention and subjective experience, were recorded among 36 young adults who received 20 minutes of either real (n = 24) or sham (n = 12) alpha-tACS over the midline parietal cortex at their individual alpha frequency (IAF) during MM in the form of paced-breathing (6 rpm). Participants who received real alpha-tACS showed an increase in lower alpha power (8-10 Hz) over the midline parietal cortex, and greater lower alpha phase coherence between left prefrontal and midline parietal cortical regions post-MM; increases in adjacent theta activity (5-8 Hz) were also noted. Comparably, similar increases in HRV, reductions in respiration rate, and levels of meditative breath attention were seen between groups, while participants randomized to real alpha-tACS reported slightly lower positive affect during the MM. Our findings suggest alpha-tACS as a means of modulating EEG alpha power and phase coherence as well as subjective experience in response to MM.