Side by side
| Compared | Caudate nucleus | Putamen |
|---|---|---|
| Where it is | Near the centre of the brain, astride the thalamus, one in each hemisphere; its head and body form part of the floor of the lateral ventricle’s front horn, and its tail curves into the temporal lobe. [2] | A rounded nucleus at the base of the forebrain, above the midbrain; going outwards from it lie the external capsule, the claustrum, the extreme capsule and the cortex of the insula. [3][5] |
| What it does | Long linked with movement, it also works in procedural learning, associative learning and the inhibitory control of action, and is part of the reward system. [2] | Regulates movements at various stages, such as preparation and execution, and influences various types of learning. [3] |
| Connects with | Dense dopamine input from the substantia nigra and input from association areas of the cortex; its output goes to the globus pallidus and the substantia nigra. [2][6] | Connected to many regions of the cerebral cortex, and to the substantia nigra, the globus pallidus, the claustrum and the thalamus. [3] |
| Size measured from the model | 64 mm front to back, 37 mm top to bottom, 32 mm side to side [4] | 43 mm front to back, 26 mm top to bottom, 18 mm side to side [4] |
Size is the box each part fits in on this one model (left caudate nucleus; left putamen), not its volume. Real brains vary. A part that comes as a left and a right copy is measured on its left copy; the right one mirrors it.
How far apart are they?
Measured from the model [4], from the left caudate nucleus to the left putamen:
- Centre to centre: 10 mm in a straight line.
- The centre of the left putamen is 4 mm further forward, level top to bottom and 9 mm further from the midline than the centre of the left caudate nucleus.
- Nearest points of the two shapes: under 1 mm apart.
A “centre” here is the average position of the points on the part’s 3D surface, so for a curved part such as a C shape it can sit outside the part itself. The nearest-points figure is measured between the corners of the simplified meshes, so a gap of 2 or 3 mm or less is within the model’s coarseness: read it as “touching or nearly so”.