Sign-tracking and goal-tracking behavior between adolescent and adult rats (2010)

Undergraduates: Randall Ung, Dawnya Bohager, Donita Robinson

Faculty Advisor: Donita Robinson
Department: Biology

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Adolescence is characterized by a number of physical, social and emotional changes in a number of species including humans and rats. In humans, adolescents have an increased propensity to abuse drugs and seek out risky activity, which could be explained by differences in behavioral and neurological systems. In this study, differences in behavior between adolescent and adult rats were analyzed when presented with a reward, specifically looking at differences in sign-tracking (ST) and goal-tracking (GT) behavior during the presentation of the cue in a Conditioned Pavlovian Approach (CPA) experiment. Rats were run through a CPA experiment where they receive 25 CS-US pairings in an operant chamber with 2 cue lights , 2 levers and cups (only one set was used.) ST and GT behavior were measured using both the time spent at and latency to approach the conditioned stimuli (CS, cue light and lever) and unconditioned stimuli (US, drinking cup), respectively. Recordings of dopamine in the nucleus accumbens (NAcc) core were measured during the final two sessions of experimentation to attempt to correlate behavior with dopamine release. Results showed that adults were more likely to portray ST behavior (more time at and shorter latencies to CS) than adolescents and adolescents were slightly more likely to show GT behavior than adults. GT increased through conditioning and the differences between age groups diminished.