Insula : neuropsychologie du cinquième lobe du cerveau

Abstract

The insula, considered as the fifth lobe of the human brain, is one of the least understood areas of the brain, and its role in neuropsychological functioning remains enigmatic for many. In recent years, electrocortical stimulation, lesion, and neuroimaging studies in humans have shed light on several functions of this brain region. However, these functions are often looked at separately. This review article aims to summarize the current knowledge about the functions of the insula in humans. After a brief description of the anatomy and connectivity of the insula, we review its role in three main domains of neuropsychological function: (1) sensorimotor processing (viscerosensory and visceromotor function, interoception, somatosensory processing, and chemosensation); (2) emotion processing (emotional experience, empathy, and risky decision-making); and (3) cognitive functions (salience processing and speech). Broad anatomo-functional subdivisions within the insular lobe itself are presented. Finally, the insula’s potential involvement in psychopathology, especially anxiety, schizophrenia, autism, and addiction, are discussed. The insula's contribution to these many functions and pathologies may largely be attributable to its role in the subjective representation of body states. This article provides clinical neuropsychologists and researchers with a global and exhaustive portrait of the insula's role in neuropsychological functioning.