We recently proposed that maintaining an interoceptive balance in the presence of significant perturbations may be a neural marker of optimal performance. Interoception can be defined as the sense of the internal body state and includes a range of sensations, such as pain, temperature, itch, tickle, sensual touch, muscle tension, air hunger, stomach pH, and intestinal tension. Taken together, these sensations provide an integrated sense of the body��s physiological condition. Thus, the interoceptive system plays a crucial role in maintaining a homeostatic state under extreme perturbations. It provides body-related information to other brain areas that monitor value or salience, is important for evaluating reward, and provides critical input to cognitive control processes. This approach is based on extensive work by Craig, Critchley, and others that has provided new insights into how the interoceptive system modulates self-monitoring and creates urges to act to maintain homeostasis. In particular, several neural substrates are thought to mediate these processes, which include the insular cortex in processing emotion-related tasks and the anterior cingulate as a link to cognitive control processes. In this study, we sought to determine whether elite warfighters, who can be considered considered an example of optimal performers in extreme environments, exhibit distinct neural processing patterns that are consistent with the notion of altered interoceptive processing. To that end, we examined offduty Navy SEALs while performing a simple emotion faceprocessing task during functional magnetic resonance imaging, and compared them with healthy male volunteers. We examined whether these elite Mulberroside-A warfighters respond distinctly to target faces exhibiting a variety of emotions. The results demonstrated that active-duty Navy SEALs exhibit a distinct pattern of brain activation during an emotion face-processing task within neural substrates that are important for interoception, indicating that elite warfighters show 7-O-ethyl-morroniside measurable processing differences compared with normal volunteers.