Functional Magnetic Resonance Imaging Analysis of Attention to One’s Heartbeat

OBJECTIVES The convergence of a neural system for monitoring external stimuli with mechanisms that process somatic information leads to the hypothesis that the anterior parietal cortex may mediate attention to a specific internal visceral signal. METHODS We measured regional brain activity through functional magnetic resonance imaging and directed subjects (6 men and 11 women) to attend to their own heartbeat, and to a heartbeat played on an external tape. RESULTS Statistical parametric brain mapping revealed the importance of right (nondominant) parietal cortex to directing attention internally to one's visceral state and focusing on a specific body signal. CONCLUSIONS The parietal activation may be taking advantage of monitoring skills typically utilized for vigilance to the external environment, in addition to working as a higher-level recognition system for signals emerging from the viscera. The finding suggests that the parietal cortex plays a central role in an interoceptive attention system that monitors bodily states.