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Hippocampal seizures and striatal regulation: a possible functional pathway
Neuroscience Letters
|December 23, 1986
Summary
The caudate nucleus (CN) tonically inhibits the hippocampus. Lesioning the CN lowers hippocampal excitability, while its destruction reveals a strio-pallido-septal pathway influencing hippocampal afterdischarges.
Area of Science:
- Neuroscience
- Neurophysiology
Background:
- The basal ganglia and hippocampus have a potential functional relationship.
- Previous studies indicate the caudate nucleus (CN) inhibits, and the globus pallidus (GP) excites, hippocampal afterdischarges (HAD).
Purpose of the Study:
- To investigate the effects of caudate nucleus (CN) destruction on hippocampal excitability.
- To examine the role of the strio-pallido-septal pathway in modulating hippocampal afterdischarges (HAD).
Main Methods:
- Electrolytic lesions of the CN were performed in 'encéphale isolé' cats.
- Hippocampal excitability and HAD threshold/duration were measured.
- Conditioning stimulation of the CN was applied in cats with prior destruction of the globus pallidus inner segment (GPi) and medial septal nucleus (MSN).
Main Results:
- CN lesions significantly reduced the threshold and increased the duration of HAD.
- Following GPi and MSN destruction, CN conditioning stimulation did not alter HAD threshold or duration.
Conclusions:
- The caudate nucleus exerts a tonic inhibitory influence on the hippocampus.
- A strio-pallido-septal pathway is suggested as the anatomical basis for this inhibitory effect on hippocampal excitability.