A key component of the diencephalon, the thalamus is a very important processing station of the brain referred to as the major sensory relay station of the brain by most experts in the field.  The structures which comprise the thalamus can be grouped anatomically into the medial nuclear group, lateral nuclear group, anterior nuclear group and an internal medullary lamina, intralaminar nuclei, midline thalamic nuclei and thalamic reticular nucleus.  I use the acronym “mail mat” to remember these seven structures.

The thalamus can also be divided into functional units.  The three functional units are relay nuclei, intralaminar nuclei and the reticular nucleus.  Relay nuclei project incoming information to the cortex and recieverecieve massive reciprocal connections back from the cortex.  Intralaminar nuclei recive input which is predominantly from the basal ganglia.  Unlike the other nuclei, the reticular nucleus only recieves inputs from the thalamic nuclei and the cerebral cortex.  This information is then projected back to the thalamus.