cerebellar climbing fiber to Purkinje cell synapse

Definition

Target type: cellularcomponent

A synapse of a climbing fiber onto the dendrites of a Purkinje cell in cerebellum. The climbing fiber originates from the inferior olivary nucleus of the medulla oblongata. [GOC:aruk, GOC:bc, PMID:19597563, PMID:23811844, PMID:5044254]

The cerebellar climbing fiber to Purkinje cell synapse is a specialized junction between two types of neurons in the cerebellum. Climbing fibers originate from the inferior olive in the brainstem and form highly complex, one-to-one connections with Purkinje cells, the sole output neurons of the cerebellar cortex. This synapse is characterized by its unique structure and function, playing a critical role in motor learning and coordination.

**Presynaptic Terminal:**
* The climbing fiber terminal, upon reaching the Purkinje cell, forms a large, complex structure that wraps around the dendritic tree of the Purkinje cell.
* This terminal is filled with numerous synaptic vesicles containing neurotransmitters, primarily glutamate.
* The terminal also contains mitochondria, providing energy for the process of neurotransmission.

**Postsynaptic Dendrite:**
* The Purkinje cell dendrite receives input from both climbing fibers and parallel fibers, another type of cerebellar neuron.
* The postsynaptic membrane of the Purkinje cell dendrite contains specialized receptors, specifically AMPA and NMDA receptors, that bind to glutamate released by the climbing fiber.
* These receptors mediate the excitatory postsynaptic potential (EPSP) generated by the climbing fiber input.

**Synaptic Transmission:**
* When an action potential arrives at the climbing fiber terminal, it triggers the opening of voltage-gated calcium channels.
* This influx of calcium ions leads to the fusion of synaptic vesicles with the presynaptic membrane, releasing glutamate into the synaptic cleft.
* Glutamate then binds to AMPA and NMDA receptors on the Purkinje cell dendrite, activating these receptors and generating a strong, complex EPSP.

**Functional Significance:**
* The climbing fiber to Purkinje cell synapse is vital for motor learning and coordination.
* It plays a crucial role in error detection and correction during motor movements.
* The strong, complex EPSP generated by the climbing fiber input is thought to induce long-term depression (LTD) in the parallel fiber to Purkinje cell synapses, contributing to the plasticity of cerebellar circuits.

**Overall, the climbing fiber to Purkinje cell synapse is a highly specialized and crucial junction that plays a critical role in cerebellar function, motor learning, and coordination.**'
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Proteins (2)

Compounds (20)