ABSTRACT
We might regard the body as a complex, elegant and sometimes incomprehensible computer. The central processor of this computer is the brain, and the primary connection to this CPU is the spinal cord. These components are called the central nervous system (CNS). The CNS receives data through a set of communication ports, processes it and sends instructions through another set of ports. Collectively these ports and their cabling are called the peripheral nervous system (PNS). The output devices control muscle activity through the autonomic and somatic nervous systems. The input devices monitor the performance of the body and keep the CNS aware of the external environment. In this chapter we shall focus on these external monitors, represented by the five senses. The importance of these senses to our general well-being cannot be overemphasized. Deprived of sensory input the brain is apt to invent its own: hallucinations of sight, sound and smell are reported by sane and normal volunteers under conditions of sensory deprivation.
