Harnessing 'time' to enhance memory: using closed-loop technology to facilitate oscillatory synchrony & support cognition
Date
2019
Authors
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Publisher
University of Delaware
Abstract
The theta rhythm (4-12 Hz) in hippocampus (HPC) has been shown to support learning and memory, often by synchronizing with interconnected brain regions to meet task demands. One key brain region with which the HPC synchronizes during spatial working memory is the medial prefrontal cortex (mPFC). Although it has been shown that unsuccessful spatial working memory performance, or manipulations that impair performance, are accompanied by decreased HPC-mPFC theta synchrony, it remains to be determined if harnessing endogenous theta synchrony, or exogenously driving theta synchrony, can be used to facilitate learning or enhance memory ability. To begin to explore these questions, we have designed a brain-machine interface to support closed-loop processes of reiteratively recording and analyzing neural input and conditionally implementing machine interventions. The first experiment uses closed-loop technology to simultaneously record local field potentials (LFPs) from both HPC and mPFC and calculate HPC-mPFC theta coherency. If high theta coherence between these regions is detected, then a command is sent to trigger a door opening which would initiate a memory task trial. The second experiment uses closed-loop technology in conjunction with optogenetics to record LFP activity from HPC, analyze power spectral density, and if HPC theta power is high, send a command to stimulate a laser in mPFC at HPC’s theta frequency to facilitate HPC-mPFC theta synchrony. The current project provides foundational proof-of-concept data that our brain-machine interface has the capability to increase the degree to which HPC and mPFC are theta-synchronous. This work provides future studies with the ability to apply this intervention in the context of enhancing learning and memory capabilities in the rodent.