The thalamus is a paired structure in the centre of the brain, sitting above the brainstem and below the cerebral cortex. It is often described as the brain's sensory switchboard because nearly all sensory information—except smell—passes through it on the way to the cortex.

The thalamus is made up of several nuclei, each specialised for a different function. The lateral geniculate nucleus relays visual information, the medial geniculate nucleus relays auditory information, and other nuclei handle somatosensory, motor, and limbic signals. It also plays a role in regulating sleep, wakefulness, and consciousness.

Key functions

• Relays sensory information to the cortex
• Routes motor signals from the basal ganglia and cerebellum
• Regulates arousal, alertness, and sleep
• Participates in memory and emotional processing