Peirre flourens suggested different parts of nervous system were responsible for different functions but conflicting evidence now some functions more spread out. Donald hebb (50 years ago) provided better understanding by showing that nerve cells are organized into larger units functioning could be understood by individual cells and larger networks they comprised. Central nervous system brain and spinal cord. Nerves bundle of nerve fibres that transmit information between cns and body"s sense organs, muscles, and glands attached to spinal cord and base of brain. Brain stem most primitive regions of brain, and its functions are basic ones control of physiological functioning and automatic behaviour (amphibians have brain stem and simple cerebellum) Cerebral hemispheres constitute large portion of brain contains parts of brain that evolved most recently: involved in behaviours of particular interest to psychology. Spinal nerves bundle of nerve fibres attached to spinal cord; conveys sensory information from body and carries messages to muscles and glands.