title: Post-training cocaine administration facilitates habit learning and requires the infralimbic cortex and dorsolateral striatum.
abstract: Human drug addiction is a complex disorder, in which exogenous substances are able to recruit and maintain behaviors involved in drug taking. Many drugs that are addictive in humans are able to act on natural brain systems for learning and memory, and while many memory systems may be affected by addictive drugs, work with operant tasks has shown that addictive drugs (e.g. cocaine and alcohol) are particularly effective in recruiting habit learning systems, compared to natural rewards. It is currently unknown if the ability of addictive drugs to facilitate habit learning depends on a direct action on habit learning systems in the brain, versus the rewarding properties of drug administration. To differentiate between these options, rats were trained to perform two actions (lever pressing), each of which was rewarded with a different natural reward. After acquiring the behavior, rats received three training sessions which were followed by post-training injections of saline or cocaine (5 or 10mg/kg, i.p.). Using sensory-specific satiety, extinction tests revealed that lever pressing for actions which were paired with saline were sensitive to devaluation (typical of goal-directed behaviors) while actions which were paired with cocaine were not sensitive to devaluation (typical of habitual behaviors). Lesions of the infralimbic or dorsolateral striatum were able to block the action of post-training cocaine injections. These data indicate that, within individual rats, cocaine injections facilitate the transition of behavior to habitual control for actions that have been recently performed, without a general facilitation of habit learning, and that this action of cocaine requires brain areas that are critical for learning natural habits.
authors.affiliation: Wabash College, Crawfordsville, IN, United States. Electronic address: torbertn@wabash.edu.
authors.forename: Neil
authors.initials: N
authors.lastname: Schmitzer-Torbert
authors.affiliation: Wabash College, Crawfordsville, IN, United States.
authors.forename: Steven
authors.initials: S
authors.lastname: Apostolidis
authors.affiliation: Wabash College, Crawfordsville, IN, United States.
authors.forename: Romeo
authors.initials: R
authors.lastname: Amoa
authors.affiliation: Wabash College, Crawfordsville, IN, United States.
authors.forename: Connor
authors.initials: C
authors.lastname: O'Rear
authors.affiliation: Wabash College, Crawfordsville, IN, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Kaster
authors.affiliation: Wabash College, Crawfordsville, IN, United States.
authors.forename: Josh
authors.initials: J
authors.lastname: Stowers
authors.affiliation: Wabash College, Crawfordsville, IN, United States.
authors.forename: Robert
authors.initials: R
authors.lastname: Ritz
mesh_terms: D000818:Animals; D003042:Cocaine / Q000008:administration & dosage*; D003216:Conditioning, Operant / Q000187:drug effects; D005108:Extinction, Psychological / Q000187:drug effects; D006184:Habits; D007858:Learning / Q000187:drug effects*; D008297:Male; D017072:Neostriatum / Q000187:drug effects*; D017397:Prefrontal Cortex / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012201:Reward
chemical_list: D003042:Cocaine
keywords: Cocaine; Dopamine; Dorsolateral striatum; Drug abuse; Habit learning; Infralimbic; Memory; Operant learning