Basal Ganglia
Published: Jul 16, 2023
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Updated: Jul 21, 2023
Written by Oseh Mathias
Founder, SpeechFit
The basal ganglia, more accurately referred to as basal nuclei (although they are commonly and erroneously known as the basal ganglia), are a group of nuclei found deep within the cerebral hemispheres and play a crucial role in a variety of brain functions[1].
The major components of the basal ganglia, as defined functionally, include:
Striatum: This is the largest component and serves as the main input nucleus of the basal ganglia[3]. It is subdivided into the dorsal striatum, which includes the caudate nucleus and the putamen, and the ventral striatum, comprising the nucleus accumbens and olfactory tubercle[4].
Globus Pallidus: It is divided into the internal globus pallidus (GPi) and the external globus pallidus (GPe). The GPi serves as one of the primary output nuclei[5].
Ventral Pallidum: This region plays a role in the limbic circuit and is a key part of the reward system. It connects to and exchanges signals with the nucleus accumbens, thalamus, and other areas[6].
Subthalamic Nucleus (STN): This structure is involved in the indirect pathway of basal ganglia circuitry[7].
Substantia Nigra: It is composed of two parts: the substantia nigra pars compacta (SNc) and the substantia nigra pars reticulata (SNr). SNc provides dopaminergic inputs to the striatum, while SNr acts as an output nucleus, similar to the GPi[8].
These structures are involved in multiple neural circuits, with roles in motor control, procedural learning, habit learning, eye movements, cognition, and emotion[9]. Inputs to the basal ganglia predominantly come from the cerebral cortex and thalamus, while outputs are sent through the GPi and SNr to the thalamus and brainstem[10]. The thalamus then sends signals back to the cortex, forming the cortico-basal ganglia-thalamo-cortical loop[11].
Author
Oseh Mathias
SpeechFit Founder
Oseh is passionate about improving health and wellbeing outcomes for neurodiverse people and healthcare providers alike.
References
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Hunt, W., & Sugano, Y. (2020). Fig 2 – Components of the basal ganglia and its anatomical relations. In The Basal Ganglia. TeachMeAnatomy. Retrieved July 19, 2023, from https://teachmeanatomy.info/neuroanatomy/structures/basal-ganglia/
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Parent, A., & Hazrati, L.N. (1995). Functional anatomy of the basal ganglia. I. The cortico-basal ganglia-thalamo-cortical loop. Brain Res Brain Res Rev, 20(1), 91-127.
Alexander, G.E., DeLong, M.R., & Strick, P.L. (1986). Parallel organization of functionally segregated circuits linking basal ganglia and cortex. Annu Rev Neurosci, 9, 357-381.