title: Coding of Event Nodes and Narrative Context in the Hippocampus.
abstract: Narratives may provide a general context, unrestricted by space and time, which can be used to organize episodic memories into networks of related events. However, it is not clear how narrative contexts are represented in the brain. Here we test the novel hypothesis that the formation of narrative-based contextual representations in humans relies on the same hippocampal mechanisms that enable formation of spatiotemporal contexts in rodents. Participants watched a movie consisting of two interleaved narratives while we monitored their brain activity using fMRI. We used representational similarity analysis, a type of multivariate pattern analysis, which uses across-voxel correlations as a proxy for neural-pattern similarity, to examine whether the patterns of neural activity can be used to differentiate between narratives and recurring narrative elements, such as people and locations. We demonstrate that the neural activity patterns in the hippocampus differentiate between event nodes (people and locations) and narratives (different stories) and that these narrative-context representations diverge gradually over time akin to remapping-induced spatial maps represented by rodent place cells.
  
  
  
  Narratives, especially in movie format, are very engaging and can be used to investigate neural mechanisms underlying cognitive functions in more naturalistic settings than that of traditional paradigms. Narratives also provide a more general context, unrestricted by space and time, that can be used to organize memories into networks of related events. For this reason, narratives are ideally suited to engage neural mechanisms underlying episodic memory formation. In this study, participants watched a movie with two interleaved narratives while their brain activity was monitored using fMRI. We show that the hippocampus, which is involved in formation of spatiotemporal contexts in episodic memory, also represents gradually diverging narrative contexts as well as narrative elements, such as people and locations.
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6525 EN Nijmegen, The Netherlands; b.milivojevic@donders.ru.nl christian.doeller@donders.ru.nl.
authors.forename: Branka
authors.identifier: 0000-0002-1850-4114
authors.initials: B
authors.lastname: Milivojevic
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6525 EN Nijmegen, The Netherlands.
authors.forename: Meryl
authors.identifier: 0000-0003-3522-8745
authors.initials: M
authors.lastname: Varadinov
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6525 EN Nijmegen, The Netherlands.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Vicente Grabovetsky
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6525 EN Nijmegen, The Netherlands.
authors.forename: Silvy H P
authors.identifier: 0000-0002-9257-8664
authors.initials: SH
authors.lastname: Collin
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6525 EN Nijmegen, The Netherlands; b.milivojevic@donders.ru.nl christian.doeller@donders.ru.nl.|Kavli Institute for Systems Neuroscience, Centre for Neural Computation, Egil and Pauline Braathen and Fred Kavli Centre for Cortical Microcircuits, NTNU, Norwegian University of Science and Technology; Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Trondheim University Hospital, 7030 Trondheim, Norway.
authors.forename: Christian F
authors.initials: CF
authors.lastname: Doeller
mesh_terms: D000328:Adult; D001307:Auditory Perception / Q000502:physiology; D001931:Brain Mapping; D004192:Discrimination, Psychological / Q000502:physiology; D005260:Female; D006624:Hippocampus / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D061212:Memory, Episodic; D009040:Motion Pictures; D011597:Psychomotor Performance / Q000502:physiology; D014796:Visual Perception / Q000502:physiology; D055815:Young Adult
keywords: context; hippocampus; memory; narrative; nodal representations; remapping