RT Journal Article
SR Electronic
T1 Emergence of stable sensory and dynamic temporal representations in the hippocampus during working memory
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 474510
DO 10.1101/474510
A1 Jiannis Taxidis
A1 Eftychios Pnevmatikakis
A1 Apoorva L. Mylavarapu
A1 Jagmeet S. Arora
A1 Kian D. Samadian
A1 Emily A. Hoffberg
A1 Peyman Golshani
YR 2018
UL http://biorxiv.org/content/early/2018/11/20/474510.abstract
AB Hippocampal networks form maps of experience through spiking sequences that encode sensory cues, space or time. But whether distinct rules govern the emergence, stability and plasticity of externally driven and internally-generated representations remains unclear. Using two-photon calcium imaging, we recorded CA1 pyramidal populations across multiple days, while mice learned and performed an olfactory, delayed, working-memory task. We observed anatomically intermixed spiking sequences, comprised of ‘odor-cells’ encoding olfactory cues, followed by ‘time-cells’ encoding odor-specific delay time-points. Odor-cells were reliably activated across trials and retained stable fields over days and different delays. In contrast, time-cells exhibited sparse, unreliable activation and labile fields that remapped over days and extended delays. Moreover, the number of odor-cells remained stable, whereas time-cells increased over days during learning of the task, but not during passive exposure. Therefore, multi-modal representations with distinct learning-related dynamics and stability can co-exist in CA1, likely driven by different neurophysiological and plasticity mechanisms.