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bioRxiv · 10.1101/676643

Increased task-dependent functional connectivity by stimulation of the hippocampal network predicts memory enhancement

Warren, K. N.·Hermiller, M. S.·Nilakantan, A. S.·Voss, J. L.
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Abstract

Successful episodic memory involves dynamic increases in the coordination of activity across distributed hippocampal networks, including the posterior-medial network (PMN) and the anterior-temporal network (ATN). We tested whether this up-regulation of functional connectivity during memory processing can be enhanced within hippocampal networks by noninvasive stimulation, and whether such task-dependent connectivity enhancement predicts episodic memory improvement. Participants received stimulation targeting either the PMN or an out-of-network control location. We compared the effects of stimulation on fMRI connectivity measured during an autobiographical memory retrieval task versus during rest within the PMN and the ATN. PMN-targeted stimulation significantly increased connectivity during memory retrieval versus rest within the PMN. This effect was not observed in the ATN, or in either network due to control out-of-network stimulation. Task-dependent increases in connectivity due to PMN-targeted stimulation within the medial temporal lobe predicted improved performance of a separate episodic memory test. It is therefore possible to enhance the task-dependent regulation of hippocampal network connectivity that supports memory processing using noninvasive stimulation.

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Warren, K. N., Hermiller, M. S., Nilakantan, A. S., Voss, J. L.. 2019-06-20. Increased task-dependent functional connectivity by stimulation of the hippocampal network predicts memory enhancement. https://doi.org/10.1101/676643

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