Experimental Psychology Seminar - John Widloski

Hippocampal replay is thought to support goal-directed behavior, yet it is unclear how flexible this mechanism remains in complex, changing environments. I will present evidence from a dynamic spatial task in which goal locations and barriers were altered across sessions. Using large-scale hippocampal recordings, we found that replay rapidly adapted to new goal and barrier configurations, generating novel, goal-directed sequences without place field remapping—highlighting a dissociation between stable sensory-driven place coding and flexible, memory-driven replay. I will also present more recent work exploring the hippocampal contribution to primacy-recency in serial learning. Rats were trained to navigate a linear maze with a series of up to 24 identical, blind-alley choice points that changed randomly across sessions. Rats learned to adapt to each new configuration, displaying errors that followed an inverted U-shape characteristic of primacy-recency. Hippocampal place cells exhibited spatial ambiguity that reflected these error patterns, suggesting a role for the hippocampus in the inference of self-localization.