The impact of pharmacological and psychological factors on measures of nicotine and tobacco reinforcement and related neural responses.

Most laboratory-based studies of drug-related reinforcement in humans tend to focus on examining the pharmacological effects of single substances or, in some cases, of their individual constituents (e.g., nicotine rather than tobacco). However, because a number of pharmacological and psychological factors can impact drug responses in humans, it is often unclear from experiments to what extent an observed drug effect can be directly attributed to the pharmacological properties of the drug. For example, indices of nicotine-related reinforcement might be influenced by the presence or absence of other psychoactive constituents found in tobacco, the route by which it is taken, its rate of delivery, and by psychological processes such as the belief that one has ingested nicotine. Because each of these factors might impact various measures of reinforcement either independently or in combination with each other, there is currently little unequivocal evidence that any given effect can be attributed to a single factor. My program of research aims to determine how various pharmacological and non-pharmacological factors impact experimental indices of drug reinforcement, using nicotine and tobacco related effects as a model, as well as to determine the extent to which these different factors involve separable underlying neural processes. In order to do so, I plan to manipulate the nicotine contents and nicotine content expectations of various products (e.g. cigarettes, vaporizers, lozenges) in a series of experiments that will assess different indices drug-related reinforcement. In addition, following the identification of specific pharmacological and psychological factors that impact the different reinforcement measures, I plan to use functional magnetic resonance imaging to identify the neural processes involved in those effects.