A pan-mammalian map of interhemispheric brain connections predates the evolution of the corpus callosum.

ABSTRACT: The brain of mammals differs from that of all other vertebrates, in having a six-layered neocortex that is extensively interconnected within and between hemispheres. Interhemispheric connections are conveyed through the anterior commissure in egg-laying monotremes and marsupials, whereas eutherians evolved a separate commissural tract, the corpus callosum. Although the pattern of interhemispheric connectivity via the corpus callosum is broadly shared across eutherian species, it is not known whether this pattern arose as a consequence of callosal evolution or instead corresponds to a more ancient feature of mammalian brain organization. Here we show that, despite cortical axons using an ancestral commissural route, monotremes and marsupials share features of interhemispheric connectivity w

SUBMITTER: Suarez R 

PROVIDER: S-EPMC6156618 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature