The thalamus (the name is derived from an ancient Greek word meaning “inner chamber”) is located roughly in the center of the brain, nestled under the cerebral hemispheres, and has several behavioral functions. Comprising two connected gray masses that resemble the size and shape of walnuts, the thalamus acts as the major relay or gateway to the cerebral cortex, with its projections spanning out to innervate all the cortical regions. Just about all information reaching the cerebral cortex, whether from the subcortical regions or from the visual, auditory, touch, and proprioceptive senses (the only exception being olfaction), is derived from the thalamus. Hence, almost everything we can know about ourselves, including our internal body states and our external awareness of the world, requires thalamic involvement. ...