Incubation of Craving: An Analysis of Short-Access Self-Administration Models Without Food Pre-Training

Incubation of craving is a behavioral phenomenon in which patients experience a time-dependent increase in cue-elicited drug craving as they progress through abstinence. Currently, the precise neurobiological mechanisms which drive incubation of craving have not yet been confirmed. Furthermore, a large proportion of the literature that encompasses current knowledge on these mechanisms uses sucrose or food pre-training procedures prior to cocaine self-administration. Literature shows that sucrose/food self-administration induces both overlapping and opposing neurochemical changes in comparison to cocaine self-administration. Therefore, the use of sucrose/food pre-training to facilitate drug self-administration could lead to confounding results for an analysis of the neurobiological underpinnings of drug craving. The experiments detailed in this thesis serve to compare the ability of two different short access (2-hour) rat models of cocaine self-administration, to elicit an incubation of craving, without the use of sucrose/food pre-training. The purpose of using a short-access (2-hour) model for cocaine self-administration rather than classical long-access (6-hour) models is to use a higher throughput procedure to study incubation of cocaine craving in rats, for the purpose of a future biochemical analysis for changes in neurobiological correlates for incubation of cocaine-craving. Additionally, this study explores the use of lower-dose short-access procedures than those described in existing literature, without the use of food training to elicit incubation of craving. The results demonstrate that both cocaine self-administration models are able to elicit comparable incubation of craving, in spite of procedural differences. Thus, relatively simple models of cocaine self-administration can be employed to study the neurobiological underpinnings of the incubation of craving