Cued Memory Retrieval Exhibits Reinstatement of High Gamma Power on a Faster Timescale in the Left Temporal Lobe and Prefrontal Cortex.
Converging evidence suggests that reinstatement of neural activity underlies our ability to successfully retrieve memories. However, the temporal dynamics of reinstatement in the human cortex remain poorly understood. One possibility is that neural activity during memory retrieval, like replay of spiking neurons in the hippocampus, occurs at a faster timescale than during encoding. We tested this hypothesis in 34 participants who performed a verbal episodic memory task while we recorded high gamma (62-100 Hz) activity from subdural electrodes implanted for seizure monitoring. We show that reinstatement of distributed patterns of high gamma activity occurs faster than during encoding. Using a time-warping algorithm, we quantify the timescale of the reinstatement and identify brain regions that show significant timescale differences between encoding and retrieval. Our data suggest that temporally compressed reinstatement of cortical activity is a feature of cued memory retrieval.SIGNIFICANCE STATEMENTWe show that cued memory retrieval reinstates neural activity on a faster timescale than was present during encoding. Our data therefore provide a link between reinstatement of neural activity in the cortex and spontaneous replay of cortical and hippocampal spiking activity, which also exhibits temporal compression, and suggest that temporal compression may be a universal feature of memory retrieval.
Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892.
Robert B
0000-0001-5166-5481
RB
Yaffe
Department of Neurological Surgery, Ohio State University Wexner Medical Center, Columbus, Ohio 43210, and.
Ammar
A
Shaikhouni
Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892.
Jennifer
0000-0002-3570-7298
J
Arai
Office of the Clinical Director, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892.
Sara K
0000-0002-7587-5085
SK
Inati
Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, kareem.zaghloul@nih.gov.
Kareem A
KA
Zaghloul
D000328:Adult; D000465:Algorithms; D001245:Association Learning / Q000502:physiology; D001931:Brain Mapping; D003463:Cues; D004569:Electroencephalography; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D065818:Gamma Rhythm / Q000502:physiology*; D006801:Humans; D008297:Male; D061212:Memory, Episodic; D011939:Mental Recall / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D017397:Prefrontal Cortex / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D013702:Temporal Lobe / Q000502:physiology*
compression; iEEG; memory; reinstatement; retrieval; timescale