Facilitating Meditation with Focused Ultrasound Neuromodulation: A First Investigation in Experienced Practitioners

This study aims to assess the validity of focused ultrasound (FUS) stimulation as a method for facilitating meditative development, which may have application for novice or intermediate meditators seeking to improve their practice. A growing body of work suggests profound benefits to health and wellbeing following consistent meditation practice; however, successfully maintaining such a practice proves to be difficult for many who attempt it. By leveraging what is known about the neural correlates of meditation, we investigate the possibility of lowering this barrier of entry via direct neuromodulation using FUS. Specifically, we applied ultrasound for 12 minutes to either the posterior cingulate cortex, bilateral caudate, or bilateral insula in experienced (vipassana) meditators while they engaged in their habitual mindfulness meditation across four separate one-hour sessions. Subjective effects reported during and after each meditation session involving stimulation are compared to a sham stimulation session, with significant differences considered evidence for an effect of FUS. Physiological effects are also reported. Our preliminary data (n=10) suggests a strong, significant improvement in self-reported meditative depth during/after Caudate stimulation while questionnaires taken after the meditation further suggest an augmented state of meditation as well as general mood induced by this condition. Compounding this, reduced heart rate and increased heart rate variability (compared to sham) were observed following FUS, again unique to the Caudate stimulation condition, while these measures were found to strongly correlate with reported depth, suggesting a mechanistic relationship between these adaptive changes in physiological arousal and successful meditation induced by targeting this structure.