TitleAffect and addiction
NameBarker, David J. (author), West, Mark O (chair), Matzel, Louis (internal member), Kusnecov, Alex (internal member), Rutgers University, Graduate School - New Brunswick,
Rats as laboratory animals,
Affective disorders ,
DescriptionAffective processing has a purported role in all aspects of addiction from initiation of drug use to relapse behavior. While roles for both negative and positive affect have been reported in humans, animal models of addiction have historically lacked an analogous measure. Recently, however, it has been proposed that the ultrasonic vocalizations (USVs) of rodents can provide valuable insight into an animal’s affective state. Rats emit USVs in two ranges, one from 18-38 kHz that has been correlated with aversive outcomes, and another from 38-80 kHz that has been linked to appetitive processing. In order to ascertain the role of affect in an animal model of cocaine addiction, the USVs of rats were measured across two experiments. First, USVs were recorded from animals in both a high dose and low dose cocaine self-administration paradigm. The results of this experiment suggested that animals in the high dose condition emitted significantly more 50-kHz USVs, whereas subjects in the low dose group emitted significantly greater numbers of 22-kHz USVs. Given the observed dose-dependent, crossover interaction of 22- and 50-kHz USVs, it was predicted that these USVs might be linked to sub-satiety and circa-satiety drug levels, respectively. In order to explicitly test this hypothesis, animals were recorded in two clamp conditions during Experiment 2: a High Clamp and a Low Clamp. During the High Clamp condition, drug levels were fixed at a constant concentration, just above subjects’ self-determined satiety threshold, for four hours. During the Low Clamp, subjects’ drug levels were fixed at a constant, sub-satiety concentration defined as fifty percent of the satiety threshold. The results of this experiment indicated that 50-kHz USVs were tied to the drug loading period early in the session, whereas 22-kHz calls were produced when subjects’ drug levels were maintained at sub-satiety levels. Overall, given their correlation with negative and positive affective states, the observed results suggest that a duality of affective processing exists during cocaine self-administration. In fact, the presence of both positive and negative affective states might suggest that the perseveration of drug-seeking in addicted subjects is due, in large part, to the additive effects of both negative and positive reinforcement.
NoteIncludes bibliographical references
Noteby David J. Barker
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.