In three separate place conditioning experiments with rats, repeated access to novel objects in one of two distinct environments conditioned an increase in preference for the novelty-paired environment. A conditioned increase in preference was found whether novel objects were paired with a randomly chosen environment or with the less preferred of two environments (conditioned against a preference). This enhanced preference did not depend on the control group employed. Control groups exposed only to the place conditioning apparatus or to both the apparatus and the novel objects showed no systematic shift in place preference. Intravenous infusions of cocaine also produced an increase in preference using the procedures employed with novel objects. Pretreatment with the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 (0.03 mg kg-1) blocked acquisition of the enhanced place preference conditioned by access to novel objects without decreasing time spent with objects or inducing a place aversion in controls. Combined, these results show that access to novel objects can serve as an appetitive stimulus like drugs of abuse and that this novelty-induced appetitive process involves NMDA receptors. These place-conditioning procedures may provide a good model for determining the behavioral and neural process underlying the appetitive effects of novelty.
|Number of pages
|Behavioural Brain Research
|Published - Feb 15 1999
Bibliographical noteFunding Information:
A National Research Service Award DA05623 supported R.A. Bevins while part of this research was conducted. Grant MH57240 to R.A. Bevins and grant DA05312 to M.T. Bardo provided funds for this research. We thank Nevia Brown, Heather Jensen and Mindy Murphy for their technical assistance. We are grateful to Susan Schenk for teaching us the surgical techniques employed in this research.
- Pavlovian conditioning
ASJC Scopus subject areas
- Behavioral Neuroscience