Comparison of the Nervous System with a Computer
When computers were first developed, it soon became apparent that these machines have many features in common with the nervous system. First, all computers have input circuits that are comparable to the sensory portion of the nervous system, and output circuits that are comparable to the motor portion of the nervous system.
In simple computers, the output signals are controlled directly by the input signals, operating in a manner similar to that of simple reflexes of the spinal cord. In more complex computers, the output is determined both by input signals and by information that has already been stored in memory in the computer, which is anal-ogous to the more complex reflex and processing mech-anisms of our higher nervous system. Furthermore, as computers become even more complex, it is neces-sary to add still another unit, called thecentral process-ing unit, that determines the sequence of all operations.This unit is analogous to the control mechanisms in our brain that direct our attention first to one thought or sensation or motor activity, then to another, and so forth, until complex sequences of thought or action take place.
Figure 45–4 is a simple block diagram of a computer. Even a rapid study of this diagram demonstrates its sim-ilarity to the nervous system. The fact that the basic components of the general-purpose computer are anal-ogous to those of the human nervous system demon-strates that the brain is basically a computer that continuously collects sensory information and uses this along with stored information to compute the daily course of bodily activity.