Drug-induced impulsivity or impulsivity-induced addiction? An Amphetamine Study
Individuals who abuse drugs, such as amphetamine (AMPH), tend to make impulsive behavioral choices that meet a particular need/desire but turn out to ultimately be maladaptive. One currently unresolved question is whether impulsivity contributes to the development and maintenance of addiction, or if repeated drug use causes impulsivity. The following study utilized an animal model of impulsivity to study how exposure to AMPH alters a rat's tendency to make impulsive behavioral choices. Rats underwent a 20-day treatment schedule of AMPH or saline and were subsequently trained to obtain a reward (e.g. sucrose pellets) by responding on one of two levers. A press on one lever resulted in delivery of a small, immediate reward (e.g. 1 pellet, no delay), whereas a press on the other lever resulted in delivery of a large reward following an increasing delay (e.g. 4 pellets after a 10-60 sec delay). Selection of the small reward lever is consistent with a maladaptive, or impulsive, behavioral choice, since rats earn more rewards by maximizing responses on the large reward lever. Preliminary results demonstrated greater base-line performance impulsivity in AMPH-treated; however, this result was not long lasting. Additionally, AMPH injections administered prior to start of the task had a dose-dependant effect on saline-treated and no effect on AMPH-treated rats.
School:
University of Illinois at Urbana-Champaign
Department:
Psychology
Research Advisor:
Joshua M. Gulley
Department of Research Advisor:
Psychology
Year of Publication:
2007