Globus Pallidus
Published: Jul 17, 2023
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Updated: Jul 26, 2023
Written by Oseh Mathias
Founder, SpeechFit
The globus pallidus is a subcortical structure located in the brain within the basal ganglia[1]. The name "globus pallidus" is Latin for "pale globe," a term reflecting its appearance.
It is located medially to the striatum, being the caudate nucleus and the putamen together, and anterior and lateral to the thalamus.
The globus pallidus is further divided into two parts: the globus pallidus internus (GPi) and the globus pallidus externus (GPe)[3].
In the the basal ganglia, which play a crucial role in various functions such as motor control, learning, executive functions, and emotions, the globus pallidus is primarily involved in the regulation of voluntary movement[4].
The globus pallidus receives input from the striatum and sends output to the thalamus, which then communicates with the cerebral cortex[5].
In very simple terms, it works like this:
The GPi sends inhibitory signals to the thalamus. When the GPi is activated, it inhibits the thalamus, reducing its activity. This in turn reduces the thalamus' excitatory effect on the cortex, leading to decreased motor activity[6].
The GPe has a different role, forming part of the indirect pathway of the basal ganglia circuit. This pathway serves to decrease the activity of the GPi and substantia nigra pars reticulata, which would lead to increased thalamic and cortical activity, and thus increased motor activity[5].
Disorders of the globus pallidus can lead to movement disorders, such as Parkinson's disease and Huntington's disease. For example, in Parkinson's disease, degeneration of the substantia nigra leads to less inhibition of the GPi, and consequently more inhibition of the thalamus and reduced motor activity[7].
Oseh is a software engineer, entrepreneur and founder of SpeechFit. Oseh is passionate about improving health and wellbeing outcomes for neurodiverse people and healthcare providers alike.
References
Bear, M. F., Connors, B. W., & Paradiso, M. A. (2016). Neuroscience: exploring the brain. Philadelphia: Wolters Kluwer.
Brain Made Simple. (2019). Basal Ganglia: Structure [Digital image]. Retrieved from https://brainmadesimple.com/basal-ganglia-structure/#What_do_you_need_to_know_about_the_globus_pallidus
Graybiel, A. M. (2008). Habits, rituals, and the evaluative brain. Annual review of neuroscience, 31.
Beukema, P., Yeh, F. C., & Verstynen, T. (2015). In vivo characterization of the connectivity and subcomponents of the human globus pallidus [Digital image]. In bioRxiv. doi: 10.1101/017806. Now published in NeuroImage doi: 10.1016/j.neuroimage.2015.07.031
Packard, M. G., & Knowlton, B. J. (2002). Learning and memory functions of the Basal Ganglia. Annual review of neuroscience, 25(1), 563-593.
Smith, Y., Bevan, M. D., Shink, E., & Bolam, J. P. (1998). Microcircuitry of the direct and indirect pathways of the basal ganglia. Neuroscience, 86(2), 353-387.
Mink, J. W. (1996). The basal ganglia: focused selection and inhibition of competing motor programs. Progress in neurobiology, 50(4), 381-425.
Wichmann, T., & DeLong, M. R. (1996). Functional and pathophysiological models of the basal ganglia. Current opinion in neurobiology, 6(6), 751-758.