title: Chronic Stress During Adolescence Impairs and Improves Learning and Memory in Adulthood.
abstract: HIGHLIGHTS This study tested the effects of adolescent-stress on adult learning and memory.Adolescent-stressed rats had enhanced reversal learning compared to unstressed rats.Adolescent-stress exposure made working memory more vulnerable to disturbance.Adolescent-stress did not affect adult associative learning or reference memory. Exposure to acute stress can cause a myriad of cognitive impairments, but whether negative experiences continue to hinder individual as they age is not as well understood. We determined how chronic unpredictable stress during adolescence affects multiple learning and memory processes in adulthood. Using male Sprague Dawley rats, we measured learning (both associative and reversal) and memory (both reference and working) starting 110 days after completion of an adolescent-stress treatment. We found that adolescent-stress affected adult cognitive abilities in a context-dependent way. Compared to rats reared without stress, adolescent-stressed rats exhibited enhanced reversal learning, an indicator of behavioral flexibility, but showed no change in associative learning and reference memory abilities. Working memory, which in humans is thought to underpin reasoning, mathematical skills, and reading comprehension, may be enhanced by exposure to adolescent-stress. However, when adolescent-stressed animals were tested after a novel disturbance, they exhibited a 5-fold decrease in working memory performance while unstressed rats continued to exhibit a linear learning curve. These results emphasize the capacity for stress during adolescence to transform the cognitive abilities of adult animals, even after stress exposure has ceased and animals have resided in safe environments for the majority of their lifespans.
authors.affiliation: Center for Brain, Behavior, and Cognition, Pennsylvania State University University Park, PA, USA ; Department of Ecosystem Science and Management, Pennsylvania State University University Park, PA, USA ; Institute of the Neurosciences, The Huck Institutes of the Life Sciences, Pennsylvania State University University Park, PA, USA.
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Chaby
authors.affiliation: Center for Brain, Behavior, and Cognition, Pennsylvania State University University Park, PA, USA ; Institute of the Neurosciences, The Huck Institutes of the Life Sciences, Pennsylvania State University University Park, PA, USA ; Department of Biobehavioral Health, Pennsylvania State University University Park, PA, USA.
authors.forename: Sonia A
authors.initials: SA
authors.lastname: Cavigelli
authors.affiliation: Center for Brain, Behavior, and Cognition, Pennsylvania State University University Park, PA, USA.
authors.forename: Amy M
authors.initials: AM
authors.lastname: Hirrlinger
authors.affiliation: Center for Brain, Behavior, and Cognition, Pennsylvania State University University Park, PA, USA.
authors.forename: James
authors.initials: J
authors.lastname: Lim
authors.affiliation: Veterinary and Biomedical Sciences, Pennsylvania State University University Park, PA, USA.
authors.forename: Kendall M
authors.initials: KM
authors.lastname: Warg
authors.affiliation: Center for Brain, Behavior, and Cognition, Pennsylvania State University University Park, PA, USA ; Department of Ecosystem Science and Management, Pennsylvania State University University Park, PA, USA ; Institute of the Neurosciences, The Huck Institutes of the Life Sciences, Pennsylvania State University University Park, PA, USA ; Department of Biology, Pennsylvania State University University Park, PA, USA.
authors.forename: Victoria A
authors.initials: VA
authors.lastname: Braithwaite
keywords: Rattus norvegicus; adolescence; chronic unpredictable stress; laboratory rat; learning; memory; reversal learning