Background:
"Conflicting hypotheses about how the interactions between HPC and neocortex contribute to memory storage and retrieval remain."
How the information is stored or modulated by the HPC and associated structures remains an open question.
During memory formation and retrieval, layer2 neocortex neurons showed engram-like properties…Distributed cortical hubsàbrainwide neural network for memory storage.
However, it was still not clear whether the oscillatory activity causally engaged memory processing in neocortex.
Coreresults:
1. 在MO, VIS, RSC脑区中观察到，在记忆形成和回溯（memrory formation and retrieval）时有theta- (low) gamma coupling.
2. Artificially inducing long-range gamma synchrony in neocortex alone restored the capacity of new memory formation and
storage in HPC-lesioned animals.
在皮层中，仅靠人工地诱导长程gamma synchrony，就可以恢复海马损伤动物的新记忆形成和存储能力。
3. HPC-->LEC-->neocortex
Keymethods:
1. LFP recording
2. iSOS: induce
cortical synchronization oscillatory signals 人工诱导gamma波
Artificial iSOS (470 nm, LED) through a cranial window (d = 6 mm) by activating the oCHiEF-expressing LEC axons in the upper layers of MO, VIS, SS, PTLp, and RSC (Fig. 3a) to simultaneously activate the circuits from LEC to the target cortices.
470 nm laser-activated neurons expressing oCHiEF-mCherry in LEC (4 ms per pulse) induced synchronization oscillatory signals (iSOS) of LFP in multiple cortical areas simultaneously.
(5.4 mW/mm2, 10 Hz or 30 Hz, 4 s on, 6 s off, 4 ms)
3. 化学遗传(hM4D(Gi))结合LFP和钙成像记录(freelymoving mice)
