{'fraction_non_alphanumeric': 0.010725010725010725, 'fraction_numerical': 0.000858000858000858, 'mean_word_length': 6.197530864197531, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Reinstatement of distributed cortical oscillations occurs with precise spatiotemporal dynamics during successful memory retrieval

Significance Our results represent significant contributions to understanding the neural mechanisms and spatiotemporal dynamics governing neural reinstatement in two important ways. First, by using a cued recall memory task, our paradigm offers experimental control over retrieval. We compare reinstatement during correct and incorrect retrieval, and provide evidence that retrieval recovers a gradually changing representation of temporal context. These data provide support for mental time travel hypothesized to underlie episodic memory. Second, leveraging the high temporal precision afforded by intracranial recordings, we investigate the precise timing of reinstatement and demonstrate that retrieval may reactivate cortical representations of a memory on a faster timescale than during encoding. Our data complement previous studies demonstrating faster replay of patterns associated with a prior episode. Reinstatement of neural activity is hypothesized to underlie our ability to mentally travel back in time to recover the context of a previous experience. We used intracranial recordings to directly examine the precise spatiotemporal extent of neural reinstatement as 32 participants with electrodes placed for seizure monitoring performed a paired-associates episodic verbal memory task. By cueing recall, we were able to compare reinstatement during correct and incorrect trials, and found that successful retrieval occurs with reinstatement of a gradually changing neural signal present during encoding. We examined reinstatement in individual frequency bands and individual electrodes and found that neural reinstatement was largely mediated by temporal lobe theta and high-gamma frequencies. Leveraging the high temporal precision afforded by intracranial recordings, our data demonstrate that high-gamma activity associated with reinstatement preceded theta activity during encoding, but during retrieval this difference in timing between frequency bands was absent. Our results build upon previous studies to provide direct evidence that successful retrieval involves the reinstatement of a temporal context, and that such reinstatement occurs with precise spatiotemporal dynamics.