Development of an "object category recognition" task for mice: Involvement of muscarinic acetylcholine receptors

Recent research suggests that rats are capable of object categorization-like processes. To study whether mice possess similar abilities, we developed a spontaneous one-trial object category recognition (OCR) task. Based on the spontaneous object recognition paradigm, mice discriminated between two otherwise equally novel objects, one from a novel category and one from a studied category. During the sample phase, mice were exposed to two different exemplars from the same category. After a retention delay, they explored a third (i.e., novel) object from that sampled category and an object from a novel category in a choice phase. Mice preferentially explored the novel category object, taken as an index of category recognition, in this OCR task when a 30-min retention delay was used. Extensive preexposure to category exemplar objects also enhanced subsequent task performance across a longer (1-h) retention delay at which mice without preexposure did not demonstrate evidence for category recognition. Prechoice administration of the acetylcholine muscarinic receptor antagonist, scopolamine, disrupted OCR performance with or without preexposure, implicating acetylcholine in category recognition. The current study presents a valuable new rodent task for the study of the mechanistic basis of categorization-like processes and its potential relevance to common cognitive disorders. (PsycINFO Database Record (c) 2019 APA, all rights reserved).