Methamphetamine Exposure Delays Formation of Habitual Behavior in Female Rats

Many psychopathologies, including addiction, have been associated with executive dysfunction and changes in behavioral control such as the development of habitual behavior. Psychostimulant drugs, likely due to the effects that these drugs have on dopamine neurotransmission in the striatum, are implicated in accelerating habit formation in male rats. Similar studies in female rats are limited. In this study, female rats received pretreatment of either methamphetamine (METH) or vehicle and were trained to the level of reinforcer-exposures typically associated with habitual behavior and then subjected to reinforcer devaluation. Habit was operationalized as an insensitivity to reinforcer devaluation. Results indicate that female rats pretreated with METH remained goal-directed while the vehicle controls demonstrated habitual behavior. These data suggest that the effect of psychostimulant exposure on habit formation may be sex-dependent, and that female rats may remain goal-directed under the influence of substances that increase dopamine in the striatum