A significant milestone in the evolution of the mammalian brain is the emergence of the corpus callosum, which is exclusively present in placental mammals.  This commissure forms the largest axon tract in the human brain and is required for the integration of sensory, motor, and associative processes between the two cerebral hemispheres. In congenital absence of the corpus callosum, callosal axons often extend toward the … Continue reading Neuroimaging shows that astrocytes are responsible for joining the 2 halves of the brain together.