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Remapping of hippocampal place cells in an unrewarded contextual memory task

Azul Silva

  • CABA,
  • Argentina
  • Azul Silva ¹
  • , Pedro Bekinschtein ²
  • , Mariano Belluscio ¹

In order to retrieve an episodic memory our brain needs to integrate the contextual information available. But usually, the information is incomplete, so which memory is retrieved in a particular situation? Pattern completion allows us to generalize and retrieve memories although information is partial. On the other side, when we need to encode a new memory without interfering with a pre-existing one, pattern separation is involved. The hippocampus has a key role in these memory processes.
Some hippocampal neurons, place cells (PC), are tuned to spatial location and generally change their tuning when sensory inputs change (remapping). But sometimes, although the context changes, PC doesn’t remap. Accumulating evidence has suggested that the hippocampal ability of storing and distinguishing between different situations and contexts, can be related with place cell’s remapping.
The aim of this project is to understand how the remapping observed in CA1 and CA3, two hippocampal regions, correlates with the evocation of contextual memories. To tackle this question we use a behavioral task that allows us to discriminate if an animal recognizes a context as new (pattern separation), or as one it already knows (pattern completion). We carried out electrophysiological recordings in CA3 and CA1 while the animal was performing the task. Preliminary results shows that there is a correlation between the amount of remapping and the memory that the animal is recalling.