title: Hippocampal and neocortical gamma oscillations predict memory formation in humans.
abstract: Functional magnetic resonance imaging (fMRI) of the human brain has shown that the hippocampus and the left temporal and frontal cortices play a key role in the formation of new verbal memories. We recorded electrical activity from 2349 surgically implanted intracranial electrodes in epilepsy patients while they studied and later recalled lists of common words. Using these recordings, we demonstrate that gamma oscillations (44-64 Hz) in the hippocampus and the left temporal and frontal cortices predict successful encoding of new verbal memories. This increase in gamma oscillations was not seen in other frequency bands, whose activity generally decreased during successful memory formation. These findings identify a role for gamma oscillations in verbal memory formation with the hippocampus and the left temporal and frontal cortices, the same regions implicated using noninvasive fMRI recording methods.
authors.affiliation: Department of Neuroscience (PBS) and Department of Psychology (MST and MJK) University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Per B
authors.initials: PB
authors.lastname: Sederberg
authors.forename: Andreas
authors.initials: A
authors.lastname: Schulze-Bonhage
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Madsen
authors.forename: Edward B
authors.initials: EB
authors.lastname: Bromfield
authors.forename: David C
authors.initials: DC
authors.lastname: McCarthy
authors.forename: Armin
authors.initials: A
authors.lastname: Brandt
authors.forename: Michele S
authors.initials: MS
authors.lastname: Tully
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kahana
mesh_terms: D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D001683:Biological Clocks; D001931:Brain Mapping / Q000379:methods; D002648:Child; D004569:Electroencephalography / Q000379:methods; D005260:Female; D006624:Hippocampus / Q000503:physiopathology*; D006801:Humans; D007858:Learning; D008297:Male; D008568:Memory; D011939:Mental Recall; D008875:Middle Aged; D019579:Neocortex / Q000503:physiopathology*; D013223:Statistics as Topic