Re: How do we get the 'convolutions' in our brain?

Dear Aileen,

Your brain does not become more wrinkled if you think alot, nor does it get bigger. In a very general sense, what happens is that the connections between different neurons in your brain are reorganized, and this allows you to learn and remember.

So why do our brains have "wrinkles"? (Incidentally, the wormy convolutions on the surface are called gyri, and the valleys are called sulci.)

As mammals have evolved, the outermost portion of the brain, called the cortex, has enlarged enormously. It has been estimated that if a human's cortex were pulled so that all of the wrinkles were removed, the skull would have to be as big as an elephant's to hold the brain.

This raises an obvious problem, since women can't birth babies with elephant sized heads. The evolutionary solution to the problem is folding the cortex up. This folding saves alot of space; think of it being similar to what happens when you wad up a piece of newspaper to make it fit into a glass.

If you have any questions or comments, please send me an email.