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Eva Karolczak '22

Keep your hippocampi on the prize: How does the brain learn goal locations?

Recent experiments have identified a subpopulation of hippocampal place cells called reward cells that encode goal locations across environments, but it is unclear how these neurons develop their characteristic activity throughout learning. To explore this question, I tracked reward cell activity in two mice from naivety to behavioral mastery as they navigated a series of virtual reality tasks. Computational analyses revealed that reward cells precessed around each reward location, first firing after reward delivery then shifting to precede it. Furthermore, this shift occurred around the time of behavioral improvement, indicating that the predictive firing of reward cells may play a key role in the facilitation of reward anticipatory behavior. These findings provide unprecedented insight towards how hippocampal subpopulations may develop – through response to a stimulus followed by precession – and in doing so support a proposed model of the hippocampus as a predictive encoder.