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Changes in the postsynaptic density with long-term potentiation in the dentate gyrus
The Journal of Comparative Neurology
|November 22, 1986
Summary
Long-term potentiation (LTP) enhances postsynaptic density (PSD) size in synapses. These structural changes, particularly in concave spine profiles, correlate with increased synaptic responsiveness, suggesting larger receptive regions contribute to potentiated responses.
Area of Science:
- Neuroscience
- Synaptic Plasticity
- Cellular Biology
Background:
- Long-term potentiation (LTP) is a key mechanism for learning and memory.
- Synaptic structure, specifically the postsynaptic density (PSD), is known to change with neuronal activity.
Purpose of the Study:
- To investigate alterations in postsynaptic density (PSD) size during long-term potentiation (LTP).
- To determine the temporal persistence and localization of these PSD changes within the molecular layer.
Main Methods:
- Electron microscopy was used to examine synaptic structures in the dentate gyrus.
- Measurements of PSD trace lengths and surface area per unit volume (SV) were performed.
- Statistical analysis, including multivariate analysis of variance, was applied to the SV data.
Main Results:
- Total PSD surface area per unit volume did not significantly change across the entire molecular layer.
- In the activated layer, total PSD surface area per unit volume showed a tendency to increase.
- A significant increase in PSD SV was observed for concave spine profiles, while nonconcave profiles showed a decrease in the middle third of the molecular layer.
Conclusions:
- LTP induces early and persistent alterations in PSD size.
- Potentiated synapses exhibit larger PSD surface area per synapse.
- These structural changes, particularly the increase in neurotransmitter receptive regions, likely contribute to enhanced synaptic responses during LTP.