Development of Anxiety-Like Behavior in the Rat




Holt, Shealyn G.

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Age has been shown as one variable that influences anxiety-like behavior in both human and animal models. Adolescence is a time of major brain growth and development, which underscores the importance of investigating emotional development during this time period. While little research has examined behavioral development during adolescence in animal models, there are data suggesting that anxiety and susceptibility to drug effects are related. The present study investigates the effect of age on anxiety-like behavior in rats, specifically examining seven time periods throughout the course of adolescence into adulthood, with analysis on four separate age groups in early adolescence, midadolescence, late adolescence, and adulthood. The results indicated that anxiety-like behavior is a function of age, with early adolescent and adult animals exhibiting higher levels of anxiety than that of their mid-adolescent and late-adolescent counterparts. More specifically, animals in the p28-p32 age cohort, when compared with the p36-p40 and p44-p48 age cohort, exhibited increased anxiety levels in total distance traveled in the open-field apparatus, percentage of time spent on the open arms of the elevated plus maze, as well as the percentage of entries into the open arms of the elevated plus maze. The results of this study may have important implications for future studies due to the fact that the development of neurobiological systems and emotions continue throughout adolescence and into adulthood, and the development of these systems may help understand future drug use and addiction models.



Rodent, Addiction, Anxiety, Elevated Plus Maze, Adolescent, Development