The central nervous system is divided into 5 major regions.
Control is rudimentary and lacks the finer degree of control which is added by higher brain centers.
The pons is a very thick bundle of fibers that connect the cerebellum to the cerebral hemispheres. The cerebellum is an essential part of motor coordination, particularly fine motor coordination and coordination of the anti-gravity muscles. Damage to the cerebellum can produce a characteristically abnormal walking gait. By doing so, it effectively controls an organism's state of alertness. Of importance is the indication that the superior colliculi pass along information about overall level of visual stimulation to the reticular activating system which in turn adjusts alertness appropriately.