Consolidation of Complex Events via Reinstatement in Posterior Cingulate Cortex.
It is well-established that active rehearsal increases the efficacy of memory consolidation. It is also known that complex events are interpreted with reference to prior knowledge. However, comparatively little attention has been given to the neural underpinnings of these effects. In healthy adults humans, we investigated the impact of effortful, active rehearsal on memory for events by showing people several short video clips and then asking them to recall these clips, either aloud (Experiment 1) or silently while in an MRI scanner (Experiment 2). In both experiments, actively rehearsed clips were remembered in far greater detail than unrehearsed clips when tested a week later. In Experiment 1, highly similar descriptions of events were produced across retrieval trials, suggesting a degree of semanticization of the memories had taken place. In Experiment 2, spatial patterns of BOLD signal in medial temporal and posterior midline regions were correlated when encoding and rehearsing the same video. Moreover, the strength of this correlation in the posterior cingulate predicted the amount of information subsequently recalled. This is likely to reflect a strengthening of the representation of the video's content. We argue that these representations combine both new episodic information and stored semantic knowledge (or "schemas"). We therefore suggest that posterior midline structures aid consolidation by reinstating and strengthening the associations between episodic details and more generic schematic information. This leads to the creation of coherent memory representations of lifelike, complex events that are resistant to forgetting, but somewhat inflexible and semantic-like in nature.
School of Psychology, University of Sussex, Falmer BN1 9QH, United Kingdom, chris.bird@sussex.ac.uk n.burgess@ucl.ac.uk.
Chris M
CM
Bird
School of Psychology, University of Sussex, Falmer BN1 9QH, United Kingdom.
James L
JL
Keidel
UCL Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, United Kingdom, King's College Hospital, Denmark Hill, London SE5 9RS, United Kingdom, and.
Leslie P
http://orcid.org/0000-0002-3244-0081
LP
Ing
UCL Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, United Kingdom, UCL Institute of Neurology, London WC1N 3BG, United Kingdom.
Aidan J
http://orcid.org/0000-0003-0882-9756
AJ
Horner
UCL Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, United Kingdom, UCL Institute of Neurology, London WC1N 3BG, United Kingdom chris.bird@sussex.ac.uk n.burgess@ucl.ac.uk.
Neil
N
Burgess
D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D005260:Female; D006179:Gyrus Cinguli / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000502:physiology*; D011939:Mental Recall / Q000502:physiology; D010775:Photic Stimulation; D011214:Practice, Psychological; D013702:Temporal Lobe / Q000502:physiology; D055815:Young Adult
MVPA; episodic memory; fMRI; hippocampus