Spatiotemporal dynamics of neural reinstatement during paired associates memory

Reinstatement;Memory;Intracranial EEG;Biomedical Engineering

Yaffe, Robert BenjaminCrone, Nathan E. ;

Johns Hopkins University

关键词: Reinstatement;    Memory;    Intracranial EEG;    Biomedical Engineering;   

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/39725/YAFFE-DISSERTATION-2016.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 摘 要 】

Reinstatement of neural activity is hypothesized to underlie our ability to mentally travel back in time in order 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. Using a time-warping algorithm, we quantify the time scale of this replay and show that on average, retrieval exhibits replay of the spectral dynamics of encoding on a faster timescale. This supports theories that memory retrieval consists of a temporally compressed replay of encoding. Our results complement previous studies showing that distributed patterns of neural activity are coordinated to encode a representation of temporal context which is then recovered during successful memory retrieval with precise spatiotemporal dynamics.