Open AccessLong-term associative memory in rats: Effects of familiarization period in object-place-context recognition test
Author(s) -
Shota Shimoda,
Takaaki Ozawa,
Yukio Ichitani,
Kazuo Yamada
Publication year - 2021
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0254570
Subject(s) - novelty , recognition memory , content addressable memory , context (archaeology) , period (music) , associative property , object (grammar) , psychology , associative learning , cognitive neuroscience of visual object recognition , cognitive psychology , computer science , neuroscience , artificial intelligence , cognition , mathematics , biology , social psychology , physics , paleontology , artificial neural network , acoustics , pure mathematics
Spontaneous recognition tests, which utilize rodents’ innate tendency to explore novelty, can evaluate not only simple non-associative recognition memory but also more complex associative memory in animals. In the present study, we investigated whether the length of the object familiarization period (sample phase) improved subsequent novelty discrimination in the spontaneous object, place, and object-place-context (OPC) recognition tests in rats. In the OPC recognition test, rats showed a significant novelty preference only when the familiarization period was 30 min but not when it was 5 min or 15 min. In addition, repeated 30-min familiarization periods extended the significant novelty preference to 72 hours. However, the rats exhibited a successful discrimination between the stayed and replaced objects under 15 min and 30 min familiarization period conditions in the place recognition test and between the novel and familiar objects under all conditions of 5, 15 and 30 min in the object recognition test. Our results suggest that the extension of the familiarization period improves performance in the spontaneous recognition paradigms, and a longer familiarization period is necessary for long-term associative recognition memory than for non-associative memory.