Globus pallidus internus (GPi)

The **globus pallidus internus** (**GPi**) is the medial segment of the globus pallidus—a subcortical nucleus that forms part of the basal ganglia system in the human brain. It serves as one of two main output nuclei for the basal ganglia network—the other being substantia nigra pars reticulata—and exerts tonic inhibitory control over thalamic nuclei involved in motor planning and execution. The GPi receives major inhibitory input from striatum neurons via GABAergic pathways and integrates additional signals from both external globus pallidus and subthalamic nucleus through direct and indirect pathways. Its primary function is regulation and fine-tuning of voluntary movements by modulating thalamocortical activity; dysfunction can result in various hyperkinetic or hypokinetic movement disorders including Parkinson’s disease and dystonia. The GPi has become an important clinical target for neuromodulatory therapies such as deep brain stimulation aimed at alleviating symptoms refractory to pharmacological treatment[1][6][7].

Other names

Internal globus pallidusMedial globus pallidusGPi

For therapies targeting this structure (e.g., DBS): - Modulation of abnormal neuronal firing patterns in the GPi to restore balance in basal ganglia-thalamo-cortical circuits.