Environmental Enrichment Promotes Adaptation to Environment Rearrangement in Younger but not Older Adolescent Rats

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Dana Cobb (Creator)
Institution
Appalachian State University (ASU )
Web Site: https://library.appstate.edu/
Advisor
Mark Zrull

Abstract: Experiences, such as environmental enrichment (EE), that allow for exploration often lead to brain changes and alter novelty-seeking behaviors, and adolescence is a developmental period in which these behaviors increase. In this study, the effects of EE during adolescence on preference for familiar objects that have been rearranged using an object-in-place (OiP) task and on neural activation in the hippocampus, which is implicated in the detection of novel spatial relationships, was investigated. Adolescent Long-Evans rats (n=16) were exposed to EE between postnatal days (PND) 25 and 48. Age-matched controls (n=16) experienced a non-enriched home-cage. Two-trial OiP testing occurred on PND 36 and 50 with two delays (15 and 60 min) in an open field containing four objects. Time in direct contact with the rearranged objects at each delay trial was measured. After behavioral testing, brain tissue was processed to examine levels of neural activity in the hippocampus. At PND 36, EE rats spent less time than no-EE rats investigating the rearranged objects at the 15 min delay (p<.0519), and more time at these objects at the 60 min delay than no-EE rats (p<.0089). However, at both delays EE rats spent an equal proportion of time investigating both sets of objects. No significant interaction of EE and OiP task delay was seen at PND 50. Histology showed 24.4% fewer active neurons in CA1 of EE rats than no-EE rats (p<.0336), no difference between groups in DG activation. While neural data support the conclusion that EE animals recognize novelty, behavioral results indicate a decrease in novelty preference in younger, but not older adolescent animals, as a result of EE.

Additional Information

Publication
Honors Project
Cobb, D. (2015) Environmental Enrichment Promotes Adaptation to Environment Rearrangement in Younger but not Older Adolescent Rats. Unpublished honors thesis.
Language: English
Date: 2015
Keywords
, object-in-place, investigation, novelty preference, exploratory strategies,

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