The central nervous system in man is made up of the brain and spinal cord. Information is collected through, the sense organs by way of the afferent nerves. These nerves also cause the muscles to contract. It is also through these nerves that information is received about the environment. The environment is external.
Date on the operation of many behavior patterns at the neurophysiological level is limited because of the lack of knowledge. However, there is an accumulation of knowledge about the brain that can give direction in the search for the biological basis for cultural behavior.
The medulla is basically used for survival, where as, the cerebrum is mostly involved in complex memory processing. The medulla is responsible for controlling breathing, swallowing, digestion, and heartbeat. It is also referred to as the switching center of the brain. It takes care of certain reflexes such as the enlargement of the pupils and the closing of the pupils due to bright light. The functions of mating and breeding are also centered in the medulla.
The cerebrum, thalamus, and hypothalamus or the limbic system regulates emotional behavior and controls metabolism and temperature. (see figure 1)
The cerebrum is also responsible for voluntary movement, thinking, personality, higher learning, consciousness, sense perception, and cultural behavior. The cortex is the center of all of the mentioned abilities. Man’s culture-related behavior lies in his language and tool skills. The cerebrum is made up of two large hemispheres which are connected by the corpus callosum. This structure allows communication back and forth through structures called commissures.
The cerebellum controls body balance, muscle tone, and voluntary movement.
Most right-handed people demonstrate what is known as left cerebral dominance. The left cerebral hemisphere controls the right hand, also controls the language performance. When the left cerebral hemisphere is truly dominant the right hemisphere will control the left hand and will be unable for the most part to produce speech. It can, however, understand simple speech. (see figure II)