Imaging for autonomic dysfunction.

Direct visualization of heart-brain interactions is the goal when assessing autonomic nervous system function. Cortical topology relevant to neuroimaging consists of the cingulate, insula, and amygdala, all of which share proximity to the basal ganglia. Significant cardiac effects stemming from brain injury are well known, including alteration of cardiac rhythms, cardiac variability, and blood pressure regulation; in some instances, these effects may correlate with neuroimaging, depending on the region of the brain involved. It is difficult to achieve visualization of areas within the brainstem that govern autonomic responses, although investigators have identified brain correlates of autonomic function with the use of functional magnetic resonance imaging and electrocardiographic data obtained simultaneously. The potential utility of brain imaging in sick patients may be limited because of challenges such as the magnetic resonance imaging environment and blunted autonomic responses, but continued investigation is warranted.