It is remarkable, but it is not exceptional.” Humans have 16 billion compared with 9 billion in gorillas and orangutans and six-to-seven billion in chimpanzees. Because it is the largest primate brain, it does have one distinctive feature: It has the highest number of cortical neurons of any primate. “People need to drop the idea that the human brain is exceptional,” said Vanderbilt University neuroscientist Suzana Herculano-Houzel, who directed the study.
It does so by determining that the prefrontal region of the brain which orchestrates abstract thinking, complex planning and decision making contains the same proportion of neurons and fills the same relative volume in non-human primates as it does in humans.
A new scientific study puts the final nail in the coffin of a long-standing theory to explain human’s remarkable cognitive abilities: that human evolution involved the selective expansion of the brain’s prefrontal cortex.
