THE BRAIN AND THE MIND

The mind is the product of the brain. Modern scientists are convinced that all the thoughts in our mind can, somehow, be reduced to physical actions in the brain. Alas, the “somehow” is important. We don't know just how the brain does it. What we think we know, though, is that computational modeling will help. To understand why we have to take a quick look at brains and neurons as physical devices.

The human brain is composed of about 5 billion (5 · 109) nerve cells, or neurons. Neurons are organized into many different functional areas, and the areas into sub-areas. The neurons themselves serve as computing and communication elements, so that you can think of “cables” of neurons transmitting signals from one region of the brain to another. A good example is the optic tract, which transmits signals from the retina of the eye (which is anatomically a part of the brain) to the primary visual cortex, which is located in the occipital region, at the back of the brain. However, you are not aware of a scene just because there is activity in the primary visual cortex. What happens next is much more complicated than we want to go into here. Suffice it to say that a tremendous amount of computing, editing, and even inferential reasoning goes on before perception occurs. The “pixel level” picture on the retina gets taken apart, augmented, interpreted, and put back together before you are aware of anything.