Charan Ranganath | Complementary learning systems in Memory and Navigation - IN PERSON

Mind Meeting

  • Datum: 29.08.2022
  • Uhrzeit: 15:30 - 17:00
  • Vortragende(r): Charan Ranganath
  • University of California at Davis, USA
  • Ort: MPI für Kognitions- und Neurowissenschaften
  • Raum: Hörsaal (C101)
  • Gastgeber: Department of Psychology
  • Kontakt:
Since the pioneering work of Ebbinghaus (1885), researchers have studied memory through lists of items, with the implicit idea that memories are composed of simple items and associations that faithfully represent past experiences. This perspective is difficult to reconcile with almost a century of research that has shown that human memory is dynamic and constructive, such that we do not replay the past, but rather, we rely on prior knowledge about events, along with a small amount of retrieved information to imagine how the past could have been. Drawing from this work, my colleagues and I have embraced a radical alternative to the dominant view in systems neuroscience: Rather than recording every moment of experience, the brain might reconstruct past events from information gathered at moments of high uncertainty or prediction error, or "event boundaries". I will present data consistent with the view that the hippocampus and subcomponents of the neocortical "Default Mode Network" serve as complementary learning systems, with the former playing a role in recording snapshots of cortical activity at event boundaries, and the latter involved in using prior knowledge to understand and reconstruct past events. Our computational modeling and empirical data suggest that this model also can account for the neural mechanisms of spatial navigation. Specifically, our recent modeling suggests that "grid cells" in the entorhinal cortex support disambiguation of similar events in episodic memory, our fMRI work suggests that hippocampal representations selectively reflect goal-relevant information during navigation, and our intracranial recordings suggest that cortico-hippocampal interactions occur disproportionately at decision points and goal locations during navigation. These data are consistent with the idea that precisely-timed interactions between the hippocampus and neocortex enable complex online computations that enable event-specific information to be integrated with general knowledge about events, environments, and tasks.
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