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bioRxiv · 10.1101/152488

Control of recollection by slow gamma dominating medium gamma in hippocampus CA1

Dvorak, D.·Radwan, B.·Sparks, F. T.·Talbot, Z. N.·Fenton, A. A.
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Abstract

Behavior is used to assess memory and cognitive deficits in animals like Fmrl-null mice that model Fragile X Syndrome, but behavior is a proxy for unknown neural events that define cognitive variables like recollection. We identified an electrophysiological signature of recollection in mouse dorsal CA1 hippocampus. During a shocked-place avoidance task, slow gamma (SG: 30-50 Hz) dominates mid-frequency gamma (MG: 70-90 Hz) oscillations 2-3 seconds before successful avoidance, but not failures. Wild-type but not Fmrl-null mice rapidly adapt to relocating the shock; concurrently, SG/MG maxima (SGdominance) decrease in wild-type but not in cognitively inflexible Fmrl-null mice. During SGdominance, putative pyramidal cell ensembles represent distant locations; during place avoidance, these are avoided places. During shock relocation, wild-type ensembles represent distant locations near the currently-correct shock zone but Fmrl-null ensembles represent the formerly-correct zone. These findings indicate that recollection occurs when CA1 slow gamma dominates mid-frequency gamma, and that accurate recollection of inappropriate memories explains Fmrl-null cognitive inflexibility.

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Dvorak, D., Radwan, B., Sparks, F. T., Talbot, Z. N., Fenton, A. A.. 2017-06-20. Control of recollection by slow gamma dominating medium gamma in hippocampus CA1. https://doi.org/10.1101/152488

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