The dorsal hippocampus is a heterogeneous structure with numerous cell types involved in generating and maintaining detailed representations of space and time. Although pyramidal neurons support associative memory through sequentially active ‘time cells’, non-neuronal contributions remain poorly understood. Here we used one-photon calcium imaging to track dorsal CA1 astrocytes across days in freely moving mice during contextual fear conditioning.
Foot shock evoked robust astrocytic calcium-event sequences with a time-compressed structure that resembled time-cell activity. Similar sequences re-emerged during later exposure to the conditioned context despite the absence of shock, but were not detected in a distinct context. Within the conditioned context, spontaneous astrocytic activity was associated with transitions across behavioral states, including freezing; this relationship was absent in the new context.
Together, these findings suggest that astrocytes contribute to hippocampal representations of the temporal structure of associative memories and motivate further study of how diverse hippocampal cell types jointly encode experience. This is a preview of subscription content, access via your institution Access Nature and 54 other Nature Portfolio journals Get Nature+, our best-value online-access subscription Receive 12 print issues and online access Prices may be subject to local taxes which are calculated during checkout Processed data used in the current study have been deposited in the Zenodo archive56 (https://zenodo.org/records/21780255). Code used in the current study has been deposited in the previously mentioned Zenodo archive.
It is also available at https://github.com/rsenne/dCA1_Paper. O’Keefe, J. & Dostrovsky, J. The hippocampus as a spatial map.
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