David Redish on cognitive rat and mental time travel

Can rats imagine the future? Neuroscientist David Redish presents evidence that rodents engage in mental time travel , constructing representations of places they have not yet visited , and argues this forces us to rethink the boundaries of animal cognition. Subscribe for more from the Convergent Science Network podcast series. David Redish joins Paul Verschure and Tony Prescott at the BCBT summer school to discuss his research on what he calls the cognitive rat. Using advanced neural decoding methods applied to hippocampal place cells, Redish demonstrates that rats generate self-consistent representations of locations they are not currently occupying , neural signatures of deliberation, imagination, and possibly insight. The conversation traces the intellectual lineage from Tolman's cognitive maps through the discovery of place cells to modern decoding techniques that allow researchers to effectively read the spatial content of ongoing neural activity. The discussion explores four distinct decision-making systems Redish identifies in the mammalian brain, reflexive, deliberative, procedural, and Pavlovian, each with largely separate neural substrates. At decision points, rats produce forward sweeps through upcoming spatial trajectories at roughly 15 times behavioral speed, while at reward locations, replay events compress spatial sequences to 40 times real time. These replay events during waking states appear to support insight and imagination, including novel shortcut sequences the animal has never physically traversed, while sleep replay tends to faithfully recapitulate actual experiences for memory consolidation. Key topics include how to define cognition operationally in non-human animals, the distinction between local and global cognitive maps, why spatial tasks reveal cognitive capacities that non-spatial paradigms miss, how mental time travel relates to episodic memory and future planning, and what the difference between waking and sleep replay tells us about the dual roles of hippocampal sharp-wave events in decision-making versus memory consolidation. Part of the Convergent Science Network podcast series from the BCBT Summer School.