Abstract
Computational models and in vivo studies in rodents suggest that the hippocampal system is not always in an optimal state for retrieval. We here show that the phase of a theta oscillation modulates neural memory reactivation in humans. EEG was recorded while participants were cued to recall previously learned word-picture associations, and multivariate pattern classifiers were trained to detect neural reactivation of the target memory. We found that classifier fidelity rhythmically fluctuated at 7-8Hz across the entire recall period. Inspired by animal work, we then computed “classifier-locked averages” to analyse how ongoing theta oscillations behaved around the time points at which the classifier indicated memory retrieval. We found strong theta (7-8Hz) phase consistency approximately 300ms before the time points of maximal neural reactivation of a memory, originating from medial temporal and occipital sources. Our findings provide important evidence that the neural signatures of memory retrieval fluctuate and are time-locked to the phase of an ongoing theta oscillation.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have