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Synaptic organization of the striatum.
1Laboratory of Cell Biology, National Institute of Mental Health, Bethesda, Maryland 20892.
Journal of Electron Microscopy Technique
|November 1, 1988
Summary
Medium spiny neurons are the primary output of the striatum, receiving cortical input to regulate basal ganglia function. Their connectivity influences motor control and is organized within striatal compartments.
Area of Science:
- Neuroscience
- Cell Biology
- Neuroanatomy
Background:
- The striatum, a key basal ganglia component, is dominated by medium spiny neurons (MSNs), which are the main output neurons.
- Understanding MSN connectivity is crucial for deciphering basal ganglia circuitry and function.
Purpose of the Study:
- To elucidate the afferent connectivity organization of medium spiny neurons in the striatum.
- To relate MSN afferent patterns to striatal compartmental organization (patches and matrix).
Main Methods:
- Combined ultrastructural neuroanatomical methods were employed.
- Analysis of synaptic connections from extrinsic and intrinsic sources onto MSNs.
Main Results:
- Cortical afferents form asymmetric synapses on MSN spines, driving striatal efferent activity.
- Dopaminergic, cholinergic, and somatostatinergic afferents form symmetric synapses on MSN dendritic shafts and spine necks, modulating cortical input.
- MSNs possess local axon collaterals that link clusters of MSNs and utilize GABA, substance P, or enkephalin.
Conclusions:
- MSN connectivity is complex, involving excitatory cortical inputs and modulatory inputs from various sources.
- The organization of afferent and efferent connections relates to the patch-matrix compartmentalization of the striatum.