Cortex, Insula, and Interoception

Abstract

Interoception as the ability of human beings to sense their internal body feelings is far beyond visceral sensations and comprises a variety of sensory modalities, including metabolic, immunologic, and autonomic status. The key area onto which interoceptive sensations project is the insular cortex in the brain. Owing to this ability, the posterior portion of the insula makes functional connections to the thalamocortical hubs as well as areas within the limbic system and the amygdala, which is historically known for its role in the perception of anger and fear. The prefrontal gyrus, anterior cingulate cortex, and several other neocortical areas add cognitive input to interoceptive perception. Granular cortices are core modulating units of interoception, while agranular cortices are directly responsible to drive perception and the resulting action that is derived from interoceptive decision making. These cortical outbound communications synchronize the activity of amygdalo-insular region with other cognitive networks and inform the rest of the brain about the interoceptive predictions and sensations, all to produce an integrated representation of internal and external body feelings and a unique form of consciousness. The granular interoceptive cortices are less prone to predictive errors, meaning a more precise interoception and factual interpretation of internal body feelings in relation to sensory input. Affective parts of our consciousness, or what we commonly call an internal sensation, enroot from predictions within the interoceptive system that might or might not be true predictions, but are congruent with overall exteroceptive and interoceptive mood of the body.