The goal of this grant is to investigate how advanced practitioners of gTum-mo (inner heat) meditation are able to tap into and manipulate the body’s homeostasis mechanisms―classically considered to be beyond voluntary control. In particular, we are interested in how this practice relates to the central and autonomic nervous systems. We propose to measure brain activity simultaneously with other physiological variables while highly-trained practitioners are performing the first stage of this meditation (before the inner heat is generated). This first stage, called ”meditating on the channels”, is itself a complex practice that requires extensive training. In line with Damasio’s “somatic marker” hypothesis and recent findings in neuroscience, we hypothesize that the practice of “meditating on the channels” involves particular patterns of activation in the anterior insular cortex (a.k.a. anterior insula) and the anterior cingulate cortex (ACC). The anterior insula is regarded as a “limbic sensory cortex” that integrates interoceptive and autonomic information with emotional salience to form a subjective sense of the physiological condition of the body, while the ACC can be regarded as “limbic motor cortex” involved with motivation and the urge to act towards maintaining the body’s homeostatic equilibrium. Our methods will combine functional magnetic resonance imaging (fMRI) with simultaneous recordings of heart rate, breathing rate, and skin conductance.