Hippocampal stimulation timed to memory reactivation shapes human sleep oscillatory dynamics and consolidation
- 1School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
Abstract
Memory consolidation during sleep depends on the precisely timed coordination of hippocampal reactivation with cortical slow oscillations and spindles. In humans this coupling has been characterised correlationally, while causal investigations have required intracranial stimulation in restricted patient cohorts or used non-invasive approaches targeting cortical regions, often obscuring the underlying sleep rhythms. Here we stimulated the human hippocampus during sleep for the first time, applying temporal interference stimulation to the left hippocampal head either concurrently with or prior to induced memory reactivation. Stimulation concurrent with reactivation reduced associative memory forgetting relative to mistimed stimulation and enhanced fast spindle amplitude, preserving the association between slow oscillation-spindle coupling and memory. This behavioural benefit was mediated by a distributed, left-lateralised set of spindle and coupling features. Non-invasively engaging deep hippocampal circuits during sleep offers both a means to probe human memory and a scalable basis for intervention where consolidation fails.
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BibTeX
@misc{okyere2026hippocampal,
title = {{Hippocampal stimulation timed to memory reactivation shapes human sleep oscillatory dynamics and consolidation}},
author = {P. Okyere and J. Li and T. Raufeisen and K. Alania and D. L. Jones and M. Steiner and E. Neufeld and N. Kuster and N. Grossman and D.-J. Dijk and R. Cohen Kadosh and U. Bartsch and V. Jaramillo and I. R. Violante},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.02.748628},
url = {https://www.biorxiv.org/content/10.64898/2026.09.02.748628v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Hippocampal stimulation timed to memory reactivation shapes human sleep oscillatory dynamics and consolidation
AU - P. Okyere
AU - J. Li
AU - T. Raufeisen
AU - K. Alania
AU - D. L. Jones
AU - M. Steiner
AU - E. Neufeld
AU - N. Kuster
AU - N. Grossman
AU - D.-J. Dijk
AU - R. Cohen Kadosh
AU - U. Bartsch
AU - V. Jaramillo
AU - I. R. Violante
PY - 2026
DA - 2026/09/02
PB - bioRxiv
DO - 10.64898/2026.09.02.748628
UR - https://www.biorxiv.org/content/10.64898/2026.09.02.748628v1
AB - Memory consolidation during sleep depends on the precisely timed coordination of hippocampal reactivation with cortical slow oscillations and spindles. In humans this coupling has been characterised correlationally, while causal investigations have required intracranial stimulation in restricted patient cohorts or used non-invasive approaches targeting cortical regions, often obscuring the underlying sleep rhythms. Here we stimulated the human hippocampus during sleep for the first time, applying temporal interference stimulation to the left hippocampal head either concurrently with or prior to induced memory reactivation. Stimulation concurrent with reactivation reduced associative memory forgetting relative to mistimed stimulation and enhanced fast spindle amplitude, preserving the association between slow oscillation-spindle coupling and memory. This behavioural benefit was mediated by a distributed, left-lateralised set of spindle and coupling features. Non-invasively engaging deep hippocampal circuits during sleep offers both a means to probe human memory and a scalable basis for intervention where consolidation fails.
ER -