The right and left hemispheres
As you may (or may not) remember from high school biology, the brain is made up of two distinct sides, or hemispheres, like the two sides of a sandwich cookie. The right hemisphere is almost completely separate from the left, with only a small band of nerve fibers connecting the two. The right hemisphere controls the muscles on the left side of the body, while the left hemisphere controls the muscles on the right.
This switch-over is hard-wired in the developing brain. As the brain and spinal cord are forming, nerves originating on one side of the body send out long extensions, called axons, toward the midline of the body. Most of the axons proceed to cross over the midline and so end up connecting with the other side of the body. For right-handed people, the hand control center is much better developed on the left side of the brain than on the right. For those who are left-handed, the better-developed nerves live in the right hemisphere.
Differences are physical, too
But left-handed brains are not simply mirror images of right-handed ones. Functions such as verbal language are usually located in the left hemisphere regardless of handedness. However, among left-handers, there is a greater likelihood that the language centers turn out to be located on the right side or on both sides of the brain. In other words, the brains of left-handed people tend to be different, and to have a greater variety of configurations, than those of right-handed people. These differences have many implications for the
different ways some left- and right-handers think.
Originally Posted by Satrana
