Remapping 2.0: Hippocampal Remapping Across Cognitive Task Demands and Age in Mice using Chronic Neuropixels 2.0

Abstract

The hippocampus is one of the most well-established systems in neuroscience, with decades of work demonstrating its crucial role in spatial navigation and memory. While remapping of these representations has been extensively characterized in response to changes in spatial context, it remains unknown whether the hippocampus remaps in response to changes in cognitive demands. In this study, we investigated whether hippocampal remapping occurs during a task-switching protocol, where mice perform a task requiring working memory and a simpler one that does not. In addition, we examined whether this form of remapping differs across age. Using Neuropixel 2.0 recordings from mice performing an accumulation of evidence towers (TT) and visually guided tasks (VG), we compared the firing-rate sequences and place-fields across conditions in both older and younger mice. Hippocampal neurons exhibited greater shifts in place field locations between tasks, indicating that remapping occurs in response to changes in cognitive demands. Statistical analysis revealed no significant difference in the degree of remapping between age groups, suggesting that the capacity to remap in response to changes in cognitive demands is preserved with age. Overall, these findings support the general view of hippocampal function in which neuronal representations are not only shaped by spatial and non-spatial contexts but also by task demands. While aging was found to impact performance, the ability of the hippocampus to reorganize representations in response to changes in cognitive demands appears to remain intact.