Diencephalon
The diencephalon, part of the limbic system, is located in the center of the brain on top of the brain stem in front of the cerebellum. The limbic system controls emotional response. It is comprised of two parts the thalamus and the hypothalamus. The thalamus is the shape of small hen’s egg and is connected through nerve fibers to all other major parts of the brain and to the spinal cord. Thus, it is a major junction point or relay station and processing center for nerve signals, controlling sensory and motor integration. Sensory nerve signals pass through it to be sorted and altered before being transmitted to the cerebral cortex. Motor nerves pass through the thalamus as well connecting the cerebral cortex, the cerebellum, and the brain stem to the muscles. The thalamus is also involved in controlling the overall level of brain activity to change our level of consciousness from deeply unconscious as in sleeping to a heightened state of alertness when exposed to danger. The thalamus and the limbic lobe of the cortex are involved in emotions and deep feelings such as anger, fear, joy, and pleasure. The hypothalamus is below the thalamus and is slightly larger than a kidney bean. The hypothalamus controls vital body processes including breathing, heartbeat, digestion, and reproduction. It is organized and controlled by the autonomic nervous system. The hypothalamus is also responsible for regulating body temperature, hunger, thirst, and biological rhythm (Farley et al., 2014) (Roca & Serrano, 1996) (Olesky, 2001) (Parker, 1997) (Walker & Wood, 2003).