Observations of the Effect of Scopolamine on Hippocampal CA1 Place Cell and Network Properties in Freely Moving Mice Using Miniscope Imaging

The hippocampus and associated cholinergic inputs regulate spatial memory in rodents. Muscarinic blockade with scopolamine results in cognition deficits usually attributed to impaired memory encoding, but effects on memory retrieval are controversial. Here, we simultaneously recorded hundreds of neurons in mouse hippocampal CA1 using calcium imaging with a miniatured fluorescent microscope to study place cell and ensemble neuronal properties in a linear track environment. We found decoding accuracy and ensemble stability were significantly reduced after the administration of scopolamine. Several other parameters including the Ca2+ event rate, number of total cells and place cells observed, spatial information content were affected including a small increase in running speed. This study enhances the understanding of cholinergic blockade on spatial memory impairment.