Insula

Insula is a portion of the cerebral cortex folded deep within the lateral sulcus (the fissure separating the temporal lobe from the parietal and frontal lobes) within the brain. The insula is believed to play a role in diverse functions usually linked to emotion or the regulation of the body's homeostasis. These functions include perception, motor control, self-awareness, cognitive functioning, and interpersonal experience.

Anatomy

The insula is divided into two parts: the larger anterior insula and the smaller posterior insula in which more than a dozen field areas have been identified. The cortical area overlying the insula towards the lateral surface of the brain is the operculum (meaning lid). The opercula are formed from parts of the frontal, temporal, and parietal lobes.

Functions

The insula has increasingly become the focus of attention for its role in body representation and subjective emotional experience. In particular, Antonio Damasio has proposed that this region plays a role in mapping visceral states that are associated with emotional experience, giving rise to conscious feelings. This is in essence a neurobiological formulation of the ideas of William James, who first proposed that subjective emotional experience (i.e., feelings) arise from the perception of bodily states.

Clinical significance

Insular cortex lesions lead to distorted self-perception and reality, with significant cognitive and perceptual deficits. This includes the inability to recognize or express disgust, distorted body image, and eating disorders. The insula also has been implicated in addiction through its role in the reward system. Damage to the insula can lead to apathy and indifference, with some patients losing the ability to become angry or happy.

See also

• Cerebral cortex
• Temporal lobe
• Parietal lobe
• Frontal lobe
• Operculum (brain)
• Antonio Damasio
• William James