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Perineuronal nets affect memory and learning after synapse withdrawal
Jiri Ruzicka1, Marketa Dalecka2, Kristyna Safrankova1
1Institute of Experimental Medicine, CAS, Prague, Czech Republic.
Translational Psychiatry
|November 15, 2022
Summary
Perineuronal nets (PNNs) are crucial for learning and memory consolidation. This study found PNNs support memory recall but do not act as a long-term memory store, with PNN-deficient animals showing better memory restoration after hibernation-like states.
Area of Science:
- Neuroscience
- Synaptic Plasticity
- Memory Research
Background:
- Perineuronal nets (PNNs) are extracellular matrix structures that ensheath mature neurons.
- PNNs regulate synaptic plasticity, learning, memory formation, retention, and extinction.
- A hypothesis suggests PNN cavities act as stable memory stores, resisting synaptic withdrawal events.
Purpose of the Study:
- To investigate the role of hippocampal PNNs in memory storage and restoration.
- To examine if PNNs stabilize memory during synaptic withdrawal induced by a hibernation-like state (HLS).
- To assess the impact of PNN absence on memory deficits and recovery after HLS.
Main Methods:
- Place memory was monitored in wild-type and PNN-deficient (chondroitinase ABC treated or aggrecan knockout) mice before and after HLS.
- Synaptic withdrawal was induced by acute HLS.
- Synapse restoration on PNN-bearing neurons was analyzed in PNN-deficient and wild-type groups.
Main Results:
- HLS induced synapse withdrawal and a memory deficit, but this was not exacerbated by PNN attenuation.
- Animals lacking PNNs demonstrated memory restoration or relearning after HLS, unlike controls.
- Absence of PNNs impacted the restoration of excitatory synapses on PNN-bearing neurons.
Conclusions:
- Hippocampal PNNs play a role in learning and memory recall.
- PNNs do not function as a long-term memory store for correcting deficits.
- PNNs may influence the dynamics of synaptic restoration after periods of withdrawal.
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