High-throughput task to study memory recall during spatial navigation in rodents

Abstract

Spatial navigation is the most frequently used behavioral paradigm to study hippocampal dependent memory formation in rodents. However, commonly used tasks can present some limitations: i) they are labor intensive, preventing the implementation of parallel testing for high-throughput experimentation; ii) yield a low number of repeated trials, curtailing the statistical power; iii) are hard to combine with neural recordings, because tethering sometimes interferes with behavior; iv) are not based on overt behavioral responses that can be precisely timed, making difficult the identification of the underlying neural events; v) produce a low spatial coverage, limiting the characterization of neuronal patterns related to spatial information. To circumvent these limitations, we developed a spatial memory task that required minimal human intervention, allowed simultaneous and unsupervised testing of several mice, and yielded a high number of recall trials per session (up to ~20). Moreover, because recall sessions could be repeated over many days, the task provided enough statistical power to characterize in detail the animals behavior during memory recall, even to quantify the decay in spatial accuracy of memories as they are stacked across days. In addition, the task is compatible with neural activity recordings. Together, these features make our task a valuable tool to start dissecting the neural circuit dynamics underlying spatial memory recall.