Protocol for calcium imaging and analysis of hippocampal CA1 activity evoked by non-spatial stimuli

The hippocampus has a major role in processing spatial information but has been found to encode non-spatial information from multisensory modalities in recent studies. Here, we present a protocol for recording non-spatial stimuli (visual, auditory, and a combination) that evoked calcium activity of hippocampal CA1 neuronal ensembles in C57BL/6 mice using a miniaturized fluorescence microscope. We describe steps for experimental apparatus setup, surgical procedures, software development, and neuronal population activity analysis. For complete details on the use and execution of this protocol, please refer to Sun et al.1