The Structure of the Human Brain
The content you've requested is available without charge only to active Sigma Xi members and American Scientist subscribers.
If you are an active member or an individual subscriber, please log in now in order to access this article.
If you are not a member or individual subscriber, you can:
Nineteenth-century phrenologists believed that characteristics such as wit or valor could be determined by feeling a person's skull—an approximation of the size and shape of their brain. As absurd as that notion seems today, it contained a nugget of truth: Brain structure does reflect many influences, including evolution, development and pathology. Using magnetic resonance imaging and computed tomography, neuroanatomists in the emerging field of brain volumetrics are discovering new answers to some old questions: What distinguishes the brains of men and women? Do genes or environment have greater influence on the size of a person's brain? What happened to the hominid brain during the evolution of Homo sapiens? Allen, Bruss and Damasio conclude with the most recent studies from their own lab, which answer the question: What happens to the parts of our brain that we don't use?