The central nervous system is comprised of the brain and the spinal cord. It is covered by a protective membrane called the dura. The brain is the control center for the central nervous system. Major divisions of the brain include the cerebral cortex, thalamus, corpus callosum, cerebellum and the brain stem.

Cerebral Cortex
The cerebral cortex, the outer surface of the cerebrum, plays a central role in many complex brain functions including thought, language, reasoning, perception, movement, behavior, perceptual awareness, language, vision and hearing. The figure below shows where these functions are located on the cerebral cortex. The right and left sides of the cerebral cortex are connected by a thick band of nerve fibers called the corpus callosum. In humans, the cerebral cortex has many ridges and grooves. A ridge on the cortex is called a gyrus and a groove is called a sulcus.

Cerebellum
The cerebellum is located behind the brain stem and plays an important role in the integration of sensory perception and motor output. Many neural pathways link the cerebellum with the motor cortex, sending information to the muscles and causing them to move. Information is also sent back to the brain, providing feedback on the position of the body in space. The cerebellum integrates this information, using constant feedback on body position to fine-tune motor movements.

Brain stem
The brain stem is a general term for the area of the brain between the thalamus and spinal cord. The brain stem includes three major divisions, the medulla, pons, and midbrain. The brainstem is responsible for the most basic functions of life such as breathing, heart rate and blood pressure.

Thalamus
The thalamus receives sensory information and relays this information to the cerebral cortex. The cerebral cortex also sends information to the thalamus, which in turn relays this information to other areas of the brain and spinal cord.