Cerebral petalias and their relationship to handedness in capuchin monkeys (Cebus apella).

Cerebral asymmetries are thought to be associated with increased hemispheric specialization of function. We investigated cerebral petalias, the protrusion of one cerebral hemisphere relative to the other, and their relationship to lateralized behavior in capuchin monkeys (Cebus apella). Magnetic resonance images of the brain and behavioral data on a coordinated bimanual task were obtained from 13 capuchins. While a significant population-level left-frontal petalia was found, this was not related to handedness. The role of the morphologically asymmetric frontal cortex in capuchins is unclear, but may reflect developmental gradients or directional selection for various behavioral functions, such as extractive foraging or social group complexity.