A spatial memory task appropriate for electrophysiological recordings.

Abstract

We developed a novel method for assessing spatial learning that is compatible with the requirements of electrophysiological recording of multiple single neurons. The behavioral task utilized a rectangular track with 8 reward boxes of which a subset contained available food (bait). Errors were scored whenever the rat investigated a non-baited box location (commission), failed to investigate a baited box location (omission), or hesitated in front of a non-baited box location (hesitation). Several controls encouraged the animal to solve the task through allocentric cues rather than through procedural strategies or simple local cue pairing. The learning curve for this task (3-5 d to criterion) was comparable to that of other spatial learning tasks when adequately motivated. The types of errors varied as the animal learned the task. Unlike other spatial learning tasks, the multi-box track allows many repeated samples of the same spatial coordinates within a short period of time to allow, for example, reliable determination of place fields while recording from hippocampal cells. Multiple trials per session also allow for high intensity training important for many learning assessments such as the timing and type of sleep involved in learning and memory.