Caudate nucleus

At a glance

English

Caudate nucleus

Latin (TA2)

Nucleus caudatus

System

Brain and spinal cord

Region

Head

Side

Paired, left and right

About the caudate nucleus

Each cerebral hemisphere holds one caudate nucleus among its basal ganglia, the deep grey-matter nuclei. It sits near the centre of the brain, arching over the thalamus. Its shape is a long C: a large rounded head in front tapers into a body and then into a slender tail. The head and body bulge into the floor and side wall of the front part of the lateral ventricle. The tail follows the ventricle down and forwards into the temporal lobe, lying above its temporal horn and ending near the amygdala.

The caudate and the putamen together make up the dorsal striatum. They are one structure in origin and microscopic make-up, but the fibres of the anterior limb of the internal capsule pass between them and split them apart, leaving only bridges of grey matter that give the striped appearance from which the name corpus striatum comes. The thalamus lies medial to the body, separated by a groove that carries the stria terminalis and the thalamostriate vein.

The caudate receives input chiefly from the association areas of the cerebral cortex, especially the prefrontal cortex, and a dense supply of dopamine fibres from the compact part of the substantia nigra. It sends output to the globus pallidus and substantia nigra pars reticulata, which return signals through the thalamus to the cortex, completing the cortico-basal ganglia-thalamo-cortical loop. Through these loops it takes part less in the mechanics of movement than in choosing and starting actions: goal-directed behaviour, learning which action leads to which result, holding spatial information in working memory, stopping unwanted responses and assessing reward. It is part of the brain's reward system.

Huntington's disease damages the striatum early, and loss of the caudate head flattens the normal bulge into the lateral ventricle on scans, giving involuntary movements with changes in mood and thinking. In Parkinson's disease loss of dopamine fibres to the striatum causes tremor at rest, rigidity and slowed movement, and loss reaching the caudate is linked to cognitive decline. Changes in caudate size or activity are also reported in obsessive-compulsive disorder, ADHD, schizophrenia and Alzheimer's disease.

Function and supply

Function

Part of the basal ganglia loops that select and start goal-directed actions, support procedural and associative learning, spatial working memory, inhibition of unwanted responses and reward processing.

Blood supply

The head and body are supplied mainly by the lenticulostriate branches of the middle cerebral artery and the recurrent artery of Heubner from the anterior cerebral artery; the tail receives the anterior choroidal artery.