island of Reil

n. Cortical area in the brain deep in the lateral (Sylvian) fissure, overlying the extreme capsule and lateral to the lenticular nucleus. It is also known as insular cortex, insular lobe, or simply, insula (island). From the cytoarchitectonic point of view, it is heterogeneous: agranular in the anterior part and granular in the posterior region. It receives information from the ventral medial nucleus of the thalamus, the ventral posterior inferior nucleus of the thalamus, and the central nucleus of the amygdala. Reciprocal connections exist between the primary somatosensory cortex and the insula. It has been proposed that the insula is involved in emotional reactions to sensory information, visceral-autonomic functions, and pain. To a significant extent, the anterior insula has limbic functions, whereas the posterior insula may be more involved in auditory and somesthetic information processing. The left insula may be directly involved in language processing, the posterior portion in phoneme recognition, and the anterior part in the organization of sequences of movements in speech; damage in the anterior insula has been related to apraxia of speech.

- AA