Anatomy

Neurons of the Cerebellar Cortex

Anatomy

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Eponym: Purkinje Cells

Structure:

The neurons of the cerebellar cortex are large, flask-shaped inhibitory neurons located within a distinct single layer between the molecular and granular layers. This layer is traditionally referred to as the Purkinje cell layer.[1]

Each of these neurons possesses an extensive, highly branched dendritic arbour that extends into the molecular layer, where synaptic input is received.[1,2] The dendrites are arranged in a planar configuration, allowing them to receive excitatory input from parallel fibres, the axons of granule cells.[2] In addition, each neuron receives powerful excitatory input from a single climbing fibre originating in the inferior olivary nucleus.[2]

The axon of each neuron projects through the granular layer to synapse primarily within the deep cerebellar nuclei.[2] These neurons are inhibitory and utilize gamma-aminobutyric acid (GABA) as their principal neurotransmitter. They constitute the sole efferent output of the cerebellar cortex.[2]

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Function:

The neurons of the cerebellar cortex integrate excitatory input from both parallel fibres and climbing fibres and transmit inhibitory output to the deep cerebellar nuclei.[2] Through this mechanism, they regulate cerebellar output involved in the coordination of voluntary movement, maintenance of posture and balance, and motor learning.[2]

As the sole efferent neurons of the cerebellar cortex, degeneration or dysfunction of these cells may result in cerebellar ataxia, dysmetria, and impaired motor coordination.[3]

References:

Moore KL, Dalley AF, Agur AMR. Clinically oriented anatomy. 6th ed. Lippincott Williams & Wilkins; 2010.
Kandel ER, Koester JD, Mack SH, Siegelbaum SA, eds. Principles of neural science. 6th ed. McGraw-Hill; 2021.
Haines DE. Neuroanatomy: an atlas of structures, sections, and systems. 9th ed. Wolters Kluwer; 2019.

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