Animals that experience adverse events in early life often have life-long changes to their physiology and behavior. Long-term effects of stress during early life have been studied extensively, but less attention has been given to the consequences of negative experiences solely during the adolescent phase. Adolescence is a particularly sensitive period of life when regulation of the glucocorticoid “stress” hormone response matures and specific regions in the brain undergo considerable change. Aversive experiences during this time might, therefore, be expected to generate long-term consequences for the adult phenotype. Here we investigated the long-term effects of exposure to chronic unpredictable stress during adolescence on adult decision-making, coping response, cognitive bias, and exploratory behavior in rats. Rats exposed to chronic unpredictable stress (e.g., isolation, crowding, cage tilt) were compared to control animals that were maintained in standard, predictable conditions throughout development. Unpredictable stress during adolescence resulted in a suite of long-term behavioral and cognitive changes including a negative cognitive bias [F(1, 12) = 5.000, P < 0.05], altered coping response [T(1, 14) = 2.216, P = 0.04], and accelerated decision-making [T(1, 14) = 3.245, P = 0.01]. Exposure to chronic stress during adolescence also caused a short-term increase in boldness behaviors; in a novel object test 15 days after the last stressor, animals exposed to chronic unpredictable stress had decreased latencies to leave a familiar shelter and approach a novel object [T(1, 14) = 2.240, P = 0.04; T(1, 14) = 2.419, P = 0.03, respectively]. The results showed that stress during adolescence has long-term impacts on behavior and cognition that affect the interpretation of ambiguous stimuli, behavioral response to adverse events, and how animals make decisions.
Keywords: adolescence, cognitive bias, coping, decision-making, chronic unpredictable stress, Rattus norvegicus, successive negative contrast
Citation: Chaby LE, Cavigelli SA, White A, Wang K and Braithwaite VA (2013) Long-term changes in cognitive bias and coping response as a result of chronic unpredictable stress during adolescence. Front. Hum. Neurosci. 7:328. doi: 10.3389/fnhum.2013.00328
Received: 01 April 2013; Accepted: 12 June 2013;
Published online: 04 July 2013.
Edited by:Louise Barrett, University of Lethbridge, Canada
Reviewed by:Carole Fureix, University of Guelph, Canada
Copyright © 2013 Chaby, Cavigelli, White, Wang and Braithwaite. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.
*Correspondence: Lauren E. Chaby, Pennsylvania State University, 410 Forest Resources Building, University Park, PA 16802, USA e-mail: firstname.lastname@example.org