Louis Pierre Gratiolet (1815–1865): The Cerebral Lobes and Fissures

Early anatomists referred to parts of the brain as 'posterior' and 'anterior.' But after comparing many primate brains, Gratiolet noticed a pattern of folds or sulci and convolutions marked by fissures of increasing complexity in the more advanced mammalian brains. The primary fissures he could also identify in the smoother ape brains. He was the first to separate four brain lobes (frontal, parietal, temporosphenoidal, occipital) and a fifth central lobe or insula. He demonstrated a sequence of closure of the cranial sutures, and he identified and named the optic radiation. Because he was reluctant to equate brain size with intelligence, Gratiolet was involved in a prolonged polemic with Broca.