Makes up 80% of the diencephalon
•Contains approximately a dozen major nuclei
•Send axons to regions of the cerebral cortex
•Nuclei act as relay stations for incoming sensory messages
•Afferent impulses converge on the thalamus
–Synapse in at least one of its nuclei
•Is the “gateway” to the cerebral cortex
•Nuclei organize and amplify or tone down signals