title: The neocortical network representing associative memory reorganizes with time in a process engaging the anterior temporal lobe.
abstract: During encoding, the distributed neocortical representations of memory components are presumed to be associatively linked by the hippocampus. With time, a reorganization of brain areas supporting memory takes place, which can ultimately result in memories becoming independent of the hippocampus. While it is theorized that with time, the neocortical representations become linked by higher order neocortical association areas, this remains to be experimentally supported. In this study, 24 human participants encoded sets of face-location associations, which they retrieved 1 or 25 h later ("recent" and "remote" conditions, respectively), while their brain activity was recorded using whole-head magnetoencephalography. We investigated changes in the functional interactions between the neocortical representational areas emerging over time. To assess functional interactions, trial-by-trial high gamma (60-140 Hz) power correlations were calculated between the neocortical representational areas relevant to the encoded information, namely the fusiform face area (FFA) and posterior parietal cortex (PPC). With time, both the FFA and the PPC increased their functional interactions with the anterior temporal lobe (ATL). Given that the ATL is involved in semantic representation of paired associates, our results suggest that, already within 25 h after acquiring new memory associations, neocortical functional links are established via higher order semantic association areas.
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, 6500 HB Nijmegen, The Netherlands. inieuwenhuis@berkeley.edu
authors.forename: Ingrid L C
authors.initials: IL
authors.lastname: Nieuwenhuis
authors.forename: Atsuko
authors.initials: A
authors.lastname: Takashima
authors.forename: Robert
authors.initials: R
authors.lastname: Oostenveld
authors.forename: Bruce L
authors.initials: BL
authors.lastname: McNaughton
authors.forename: Guillén
authors.initials: G
authors.lastname: Fernández
authors.forename: Ole
authors.initials: O
authors.lastname: Jensen
mesh_terms: D001245:Association Learning; D003627:Data Interpretation, Statistical; D004569:Electroencephalography; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008568:Memory / Q000502:physiology*; D011939:Mental Recall / Q000502:physiology; D019579:Neocortex / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology; D010775:Photic Stimulation; D017397:Prefrontal Cortex / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D013702:Temporal Lobe / Q000502:physiology*; D013826:Theta Rhythm / Q000502:physiology; D055815:Young Adult