Thalamus

About the Thalamus

The thalamus is a paired, egg shaped mass of gray matter sitting on either side of the third ventricle, deep within the brain. It is made up of many distinct nuclei and acts as the main relay station between the cerebral cortex and the rest of the nervous system. Nearly all sensory information except smell passes through a specific thalamic nucleus before reaching the cortex: visual signals through the lateral geniculate nucleus, auditory signals through the medial geniculate nucleus, and touch and pain through the ventral posterior nuclei. The thalamus also links the cortex with the basal ganglia and cerebellum in circuits that control movement, and it plays important roles in attention, sleep and wakefulness, and consciousness. Strokes affecting the thalamus can cause sensory loss and, in some cases, a chronic pain condition known as thalamic pain syndrome. Deep brain stimulation targeting thalamic nuclei is used for some movement disorders such as essential tremor.