Deep grey nuclei — caudate, putamen and globus pallidus — that help select and smooth voluntary movement
Basal ganglia — the motor loops of the forebrain.
Anatomy · Brain & nerves
Basal ganglia
A group of deep nuclei
Brain · deep cerebral nuclei
A group of interconnected masses of grey matter buried deep within each cerebral hemisphere, chiefly the caudate nucleus, the putamen and the globus pallidus, with the subthalamic nucleus and substantia nigra as close functional partners. They select and smooth voluntary movement and help form habits, and their dysfunction gives rise to Parkinson's disease and Huntington's disease.
How to spot them
- ▸Deep grey masses lateral to the thalamus, separated from it by a band of white matter, the internal capsule
- ▸The caudate is a comma-shaped nucleus that arches alongside the lateral ventricle, with a head and a long tail
- ▸The putamen and globus pallidus together form a lens-shaped mass called the lentiform nucleus
- ▸Caudate and putamen are joined by thin strands of grey matter, giving the striped appearance that inspired the term striatum
What to know
Includes a comma-shaped nucleus, named from the Latin for 'tail', that arches around the lateral ventricle
Basal ganglia — the caudate nucleus is one of its members.
Two of its nuclei fuse into a lens-shaped mass lying just outside the internal capsule
Basal ganglia — the putamen and globus pallidus form the lentiform nucleus.
Loss of dopamine-producing cells in a midbrain nucleus that supplies it causes tremor, rigidity and slowness of movement
Basal ganglia — Parkinson's disease follows loss of the substantia nigra input.
Inherited degeneration of the caudate and putamen causes involuntary dance-like movements and dementia
Basal ganglia — Huntington's disease, from a CAG repeat expansion on chromosome 4.
Its largest part gets the name 'striped body' from strands of grey matter crossing a band of white fibres
Basal ganglia — the striatum (caudate plus putamen), striped by the internal capsule.
A target for implanted electrodes in advanced Parkinson's disease, via the subthalamic nucleus or globus pallidus
Basal ganglia — deep brain stimulation.
Key ideas
- They work as a brake and accelerator on movement: the direct pathway releases wanted movements, the indirect pathway suppresses unwanted ones.
- Dopamine from the substantia nigra tunes the balance between these pathways.
Quick-fire facts
- •The main nuclei are the caudate, putamen and globus pallidus; the subthalamic nucleus and substantia nigra are usually included as functional members
- •Caudate plus putamen make up the striatum; putamen plus globus pallidus make up the lentiform nucleus
- •The nucleus accumbens, part of the ventral striatum, is involved in reward
- •The internal capsule runs between the caudate, the thalamus and the lentiform nucleus
- •Parkinson's disease is linked to loss of dopamine-producing neurons in the substantia nigra
- •Huntington's disease was described by George Huntington in 1872; the HTT gene is on chromosome 4
- •Despite the name, 'ganglia' strictly refers to groups of neurons outside the central nervous system; the term is a historical misnomer here
- •Deep brain stimulation of the subthalamic nucleus or globus pallidus internus is used for Parkinson's disease
- •Also involved in habit formation and procedural learning
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Sources
- TeachMeAnatomy — Basal ganglia
- OpenStax — 13.2 The Central Nervous System — Anatomy and Physiology 2e