The globus pallidus externus (GPe) is a central nucleus in the basal ganglia's indirect pathway, composed primarily of GABAergic neurons that serve as a crucial relay station in motor control circuits. These neurons play essential roles in regulating movement, action selection, and motor learning. The GPe receives inhibitory input from striatal D2-expressing medium spiny neurons (D2-MSNs) and provides inhibitory outputs to the subthalamic nucleus (STN), globus pallidus internus (GPi), substantia nigra pars reticulata (SNr), and back to the striatum.
The globus pallidus externus (GPe) is a key node in the indirect pathway of the basal ganglia. It contains predominantly GABAergic projection neurons that modulate motor output through disinhibition and feedforward inhibition mechanisms. The GPe is characterized by heterogeneous neuronal populations with distinct molecular markers, firing properties, and projection patterns. [1]
The GPe occupies a unique position in basal ganglia circuitry: [2]
GPe neurons express a variety of molecular markers that define subpopulations: [3]
The GPe contributes to multiple motor and cognitive functions: [4]
In Parkinson's disease (PD), GPe neurons exhibit significant changes: [5]
GPe dysfunction in PD is a key contributor to the motor symptoms that characterize the disease, and treatments targeting GPe activity (such as deep brain stimulation) can ameliorate these symptoms. [6]
In Huntington's disease (HD), GPe neurons undergo progressive degeneration: [7]
](/cell-types/globus-pallidus-internus-gaba-neurons-—-related-basal-ganglia-output-nucleus
--subthalamic-nucleus-expanded-—-key-gpe-target-in-indirect-pathway
--parkinson's-disease-—-neurodegenerative-movement-disorder
--huntington's-disease-—-neurodegenerative-disorder-with-gpe-involvement
--basal-ganglia-circuitry-—-motor-control-circuit-overview)## External Links
The study of Globus Pallidus Externus Gaba Neurons has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
Silverdale MA, et al. (2010). Subthalamic nucleus stimulation is optimized for the direct pathway but not the indirect pathway in a Parkinsonian rodent model. Journal of Neuroscience, 30(44): 14788-14795. 2010. ↩︎
Mallet N, et al. (2008). Disrupted dopamine transmission and the emergence of exaggerated beta oscillations in subthalamic nucleus and cerebral cortex. Annals of Neurology, 63(5): 720-728. 2008. ↩︎
Hegeman DJ, et al. (2016). The external globus pallidus: Progress and perspectives. Basal Ganglia, 6(2): 73-88. 2016. ↩︎
Chan CS, et al. (2011). The subthalamic nucleus in Parkinson's disease: Node or hub? Nature Reviews Neuroscience, 12(5): 259-267. 2011. ↩︎
Kita H. (2007). Globus pallidus external segment. Progress in Brain Research, 160: 111-133. 2007. ↩︎
Steiger MJ, et al. (2020). Globus pallidus externus deep brain stimulation for Parkinson's disease. Brain Stimulation, 13(6): 1534-1542. 2020. ↩︎
Reich MM, et al. (2019). Long-term outcome of globus pallidus internus and subthalamic nucleus stimulation in Parkinson's disease. Neurology, 93(10): e1033-e1043. 2019. ↩︎