Organ
Globus pallidus
Pallidal circuits help select and regulate movement
High-yield
GPi is a major basal-ganglia output nucleus; GPe has a different role within the circuit. In the simplified motor-loop model, reducing GPi inhibition allows thalamocortical activity to increase. Real movement control also depends on timing and patterns of neural activity.
Overview
The globus pallidus occupies the medial portion of the lentiform nucleus, beside the putamen. A sheet of white matter separates its external and internal segments. The external segment participates in interconnected basal-ganglia circuits, including the indirect pathway. The internal segment is a major output station, sending inhibitory signals to the thalamus and other motor-related targets.
Reference facts
- Location
- Deep cerebral gray matter between the putamen laterally and internal capsule medially
- Parts
- External segment, GPe, and internal segment, GPi, separated by the medial medullary lamina
- Blood supply
- Lenticulostriate and anterior choroidal arteries, with smaller anterior cerebral/Heubner contributions; territories vary
- Relations
- Medial component of the lentiform nucleus; pallidal output bundles pass around or through the internal capsule toward diencephalic targets
- Function
- Both segments use predominantly inhibitory GABA signaling. GPi projects to motor thalamic regions, including VA and VL, while GPe participates in internal basal-ganglia feedback circuits
Clinical correlation
GPi is a target for deep brain stimulation in selected people with Parkinson disease or dystonia. This illustrates the importance of pallidal circuit activity in movement disorders; it does not mean stimulation is suitable for every patient with these conditions.
Frequently asked questions
Where is the globus pallidus located?
Deep cerebral gray matter between the putamen laterally and internal capsule medially.
What does the globus pallidus do?
Both segments use predominantly inhibitory GABA signaling. GPi projects to motor thalamic regions, including VA and VL, while GPe participates in internal basal-ganglia feedback circuits.
What are the parts of the globus pallidus?
The parts of the globus pallidus are the external segment, GPe, and internal segment, GPi, separated by the medial medullary lamina.
What is the blood supply of the globus pallidus?
Lenticulostriate and anterior choroidal arteries, with smaller anterior cerebral/Heubner contributions; territories vary.