Free Republic

In the continuing effort to understand the human brain, the mysteries keep piling up. Consider what scientists are up against. Stretched flat, the human neocortex — the center of our higher mental functions — is about the size and thickness of a formal dinner napkin. With 100 billion cells, each with 1,000 to 10,000 synapses, the neocortex makes roughly 100 trillion connections and contains 300 million feet of wiring packed with other tissue into a one-and-a-half-quart volume in the brain. These cells are arranged in six very similar layers, inviting confusion. Within these layers, different regions carry out vision, hearing,...

The Triune Brain illustration from The three units of the human Brain -Júlio Rocha do Amaral, & Jorge Martins de Oliveira (image somewhat degraded to speed up download) Paul MacLean discovery of the The Triune Brain The Reptilian Brian The Limbic System (Paleomammalian brain) The Neocortex (Neomammalian brain) Links The neurologist Paul MacLean has proposed that our skull holds not one brain, but three, each representing a distinct evolutionary stratum that has formed upon the older layer before it, like an archaeological site :He calls it the "triune brain."  MacLean, now the director of the Laboratory of Brain Evolution and...