Hemispheric Asymmetries

Hemispheric asymmetry is a term used to describe either anatomical or functional distinctions between the two brain hemispheres. Structurally, the two hemispheres are quite similar, but they are not fully symmetrical. There are minor variations in cortical and subcortical anatomy that differentiate the left hemisphere from the right hemisphere. These variations likely evolved over time with the acquisition of specialized cognitive abilities that are lateralized to one hemisphere or the other. In the intact brain, the unique abilities of each hemisphere are seamlessly integrated by interhemispheric communication pathways. The largest of these is the corpus callosum, a white matter pathway that runs nearly the entire length of the brain and connects the two cerebral hemispheres.

Anatomical differences between the hemispheres were noted by early neuroanatomists. Insights ...