Comparative insights into insula structure and function.

The insular cortex has become an increasingly important focus of neuroscientific research because of its broad involvement in psychological and behavioral processes and its dysfunction in neuropsychiatric, developmental, degenerative and metabolic disorders. The insula is easily imaged in the human brain and is also a key target for both fundamental and translational studies in nonhuman animals. However, owing to a dearth of truly comparative studies on the insula, the extent to which this region shares structural and functional homologies between humans, monkeys and rodents remains incompletely understood. Here, we systematically evaluate current knowledge regarding homologies in the insula among model species and humans. We examine the strengths and limitations of various laboratory species for investigating the insula, and discuss how these factors influence the interpretation of findings and their application to the human insula. Finally, we propose research directions aimed at strengthening translational insula research and enhancing our understanding of cross-species similarities and differences.