Human neocortical oscillations exhibit theta phase differences between encoding and retrieval.
We analyzed intracranial brain activity recorded from human participants during the performance of a working-memory task. We show that 6-13 Hz activity exhibits consistent phase across trials following experimental stimuli, and that this phase significantly differs between study and test stimuli. These findings suggest that oscillatory phase reflects the encoding-retrieval state of neural networks, supporting predictions of recent models of memory.[Hasselmo, M.E., Wyble, B.P., and Bodelon, C., 2002. A proposed function for hippocampal theta rhythm: Separate phases of encoding and retrieval enhance reversal of prior learning. Neural Comput. 14 793-817.; Judge, S.J., Hasselmo, M.E., 2004. Theta rhythmic stimulation of stratum lacunosum-moleculare in rat hippocampus contributes to associative LTP at a phase offset in stratum radiatum. J. Neurophys. 92 1516-1624.].
Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA. rizzuto@caltech.edu
Daniel S
DS
Rizzuto
Joseph R
JR
Madsen
Edward B
EB
Bromfield
Andreas
A
Schulze-Bonhage
Michael J
MJ
Kahana
D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D002648:Child; D004567:Electrodes, Implanted; D004569:Electroencephalography; D004833:Epilepsy, Temporal Lobe / Q000503:physiopathology; D005260:Female; D005583:Fourier Analysis; D006624:Hippocampus / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D019579:Neocortex / Q000503:physiopathology*; D009415:Nerve Net / Q000503:physiopathology*; D009991:Oscillometry; D011930:Reaction Time / Q000502:physiology; D012016:Reference Values; D012815:Signal Processing, Computer-Assisted; D013826:Theta Rhythm; D014706:Verbal Learning / Q000502:physiology*