Theta-phase dependent neuronal coding during sequence learning in human single neurons

Leila Reddy*, Matthew W. Self, Benedikt Zoefel, Marlène Poncet, Jessy K. Possel, Judith C. Peters, Johannes C. Baayen, Sander Idema, Rufin VanRullen, Pieter R. Roelfsema

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

The ability to maintain a sequence of items in memory is a fundamental cognitive function. In the rodent hippocampus, the representation of sequentially organized spatial locations is reflected by the phase of action potentials relative to the theta oscillation (phase precession). We investigated whether the timing of neuronal activity relative to the theta brain oscillation also reflects sequence order in the medial temporal lobe of humans. We used a task in which human participants learned a fixed sequence of pictures and recorded single neuron and local field potential activity with implanted electrodes. We report that spikes for three consecutive items in the sequence (the preferred stimulus for each cell, as well as the stimuli immediately preceding and following it) were phase-locked at distinct phases of the theta oscillation. Consistent with phase precession, spikes were fired at progressively earlier phases as the sequence advanced. These findings generalize previous findings in the rodent hippocampus to the human temporal lobe and suggest that encoding stimulus information at distinct oscillatory phases may play a role in maintaining sequential order in memory.
Original languageEnglish
Article number4839
JournalNature Communications
Volume12
Issue number1
DOIs
Publication statusPublished - 1 Dec 2021

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