High-Throughput Task to Study Memory Recall During Spatial Navigation in Rodents

Spatial navigation is one of the most frequently used behavioral paradigms to study memory formation in rodents. Commonly used tasks to study memory are labor-intensive, preventing the simultaneous testing of multiple animals and tend to yield a low number of trials, curtailing the statistical power. Moreover, they are not tailored to be combined with neurophysiology because they are not based on overt stereotyped behavioral responses that can be precisely timed. Here we present the 8-port maze task to study long-term memory formation and recall during spatial navigation. The task consists of a learning session during which mice need to find the rewarding port that changes from day to day. Following learning, there is a 2 hr recall session during which mice report the location of the memorized rewarding port. During the recall sessions, the animals repeatedly report the remembered port over many trials (up to ~20) without receiving reward (i.e. no positive feedback). Interestingly, mice also show memory regarding ports learned on previous days (up to 72 hours). We have been able to pharmacologically manipulate these memories individually. The 8-port maze task required minimal human intervention, allowing simultaneous and unsupervised testing of several mice, yielding a high number of recall trials per session over many days (up to 200). In addition, the task is compatible with neural activity recordings. Our novel methodology opens the door to investigate with high statistical power the mechanisms underlying long-term memories during formation and recall behavior, something that has not been previously achieved with other tasks.