Insula

The insula is a triangular area of cortex in the floor of the lateral sulcus. It can be seen only when the overlying opercula (frontal, frontoparietal and temporal) are pulled apart. It is outlined by the circular sulcus and divided by the central insular sulcus into short gyri in front and long gyri behind. Its anteroinferior apex, the limen insulae, is continuous with the anterior perforated substance. Deep to it lie the extreme capsule, the claustrum, the external capsule and the putamen. The M2 (insular) segments of the middle cerebral artery run over its surface.

The insula is the main cortical area for interoception, the sense of the body's internal state: heartbeat, breathing, visceral fullness, temperature, itch and pain. It contains the primary gustatory cortex (anterior insula and frontal operculum, which receive taste from VPM). It also has visceromotor (autonomic) and vestibular functions. The anterior insula, together with the anterior cingulate cortex, forms the salience network, which flags important stimuli. It contributes to the emotional colour of pain, disgust, empathy, craving and subjective awareness.