The thalamus is a part of the brain that is found in the third ventricle. It is egg-shaped and along with the hypothalamus comprises the area known as the diencephalon.

The thalamus acts as a central relay station for all sensory impulses travelling from other parts of the spinal cord and brain to the cerebral cortex (outer portion of the brain). It receives all sensory impulses (except those associated with smell) and directs them to the appropriate regions of the cerebrum for appropriate interpretation and integration. The thalamus acts as the last portion of the brain for sensory input before the cerebrum.

The thalamus connects to various parts of the brain via specialized nerve fibers that originate in the upper part of the reticular activating system (RAS). The RAS (which extends from the medulla oblongata to the thalamus) sorts out stimuli from the sense organs and passes on...