Exercise modulates human hippocampal-cortical ripple dynamics

Cardenas, A. R.; Ramirez-Villegas, J. F.; Kovach, C. K.; Gander, P. E.; Cole, R. C.; Grossbach, A. J.; Kawasaki, H.; Greenlee, J. D.; Howard, M. A.; Nourski, K. V.; Banks, M. I.; Voss, M. W.

doi:10.1101/2023.05.19.541461

bioRxiv · 10.1101/2023.05.19.541461

Exercise modulates human hippocampal-cortical ripple dynamics

Cardenas, A. R.·Ramirez-Villegas, J. F.·Kovach, C. K.·Gander, P. E.·Cole, R. C.·Grossbach, A. J.·Kawasaki, H.·Greenlee, J. D.·Howard, M. A.·Nourski, K. V.·Banks, M. I.·Voss, M. W.

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Abstract

Physical exercise acutely improves hippocampus-dependent memory. Whereas animal studies have offered cellular- and synaptic-level accounts of these effects, human neuroimaging studies show that exercise improves hippocampal-cortical connectivity at the macroscale level. However, the neurophysiological basis of exercise-induced effects on hippocampal-cortical circuits remains unknown. Experimental evidence supports that hippocampal sharp wave-ripples (SWR) play a critical role in learning and memory. Coupling between SWRs in the hippocampus and neocortex may reflect modulations in inter-regional connectivity required by mnemonic processes. Here, we examine the hypothesis that exercise modulates hippocampal-cortical ripple dynamics in the human brain. We performed intracranial recordings in epilepsy patients undergoing pre-surgical evaluation, during awake resting state, before and after an exercise session. Exercise increased ripple rate in the hippocampus. Exercise also enhanced the coupling and phase-synchrony between cortical ripples in the limbic and the default mode (DM) cortical networks and hippocampal SWRs. Further, higher heart rate during exercise, reflecting exercise intensity, was related to a subsequent increase in resting state ripples across specific cortical networks including the DMN. These results offer the first direct evidence that a single exercise session elicits changes in ripple events, a well-established neurophysiological marker of mnemonic processing. The characterization and anatomical distribution of the described modulation points to hippocampal ripples as a potential mechanism by which exercise elicits its reported short-term effects in cognition.

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Cardenas, A. R., Ramirez-Villegas, J. F., Kovach, C. K., Gander, P. E., Cole, R. C., Grossbach, A. J., Kawasaki, H., Greenlee, J. D., Howard, M. A., Nourski, K. V., Banks, M. I., Voss, M. W.. 2023-05-22. Exercise modulates human hippocampal-cortical ripple dynamics. https://doi.org/10.1101/2023.05.19.541461

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