The investigators' aim is to test the prediction that sweet taste perception enhances the ability of nicotine to induce neural plastic changes in brain reward circuits to increase the saliency, liking and brain reactivity to the sight and vaporized flavor of electronic cigarettes (e-cigarettes).

Alternative tobacco products are becoming increasingly available in the US market and are promoted as potentially less deleterious compared to cigarettes. These products are increasing in usage as either a substitution for cigarette smoking or in addition to smoking. One particular appeal is that they often combine nicotine with sweet taste and flavors, which are themselves reinforcing. The primary goal of this project is to determine if sweet taste can potentiate the reinforcing properties of nicotine. Similar to nicotine, cues predicting the availability of carbohydrates can stimulate intake, even in the absence of hunger. The investigators have developed a novel flavor-nutrient conditioning paradigm to study the reinforcing properties of carbohydrates. Novel flavors are paired with 0 or 113 kcal carbohydrate and increases in flavor-cue reactivity (change in liking and brain response) when later sampled in the absence of the carbohydrate provide a measure of the reinforcing potency. For smokers, the aroma of tobacco is a potent cue that can promote smoking behavior. Using a modified version of our conditioning paradigm, our specific aim is to test the prediction that sweet taste perception enhances the ability of nicotine to induce neural plastic changes in brain reward circuits to increase the saliency, liking and brain reactivity to the sight and vaporized flavor of electronic cigarettes (e-cigarettes). Participants will smoke e-cigarettes that contain nicotine and an unsweetened vaporized flavor, nicotine and a sweet vaporized flavor or only a sweet vaporized flavor (no nicotine). The investigators predict that response in the nucleus accumbens and hypothalamus to the sight and vaporized flavor of the e-cigarette that was paired with nicotine and sweet taste will be greater than the responses to the sight and vaporized flavors associated with the other e-cigarettes. The investigators further predict that liking and wanting will increase more for the sight and vaporized flavor associated with both nicotine and sweet taste. This finding would provide strong evidence that sweet taste potentiates the reinforcement potency of nicotine and could therefore promote use.

Inclusion Criteria:

• right handed
• non-daily smoker
• english speaking

Exclusion Criteria:

• serious or unstable medical illness (e.g., cancer);
• past or current history of alcoholism or consistent drug use;
• current and history of major psychiatric illness as defined by the DSM-IV criteria including eating disorders,
• medications that affect alertness (e.g., barbiturates, benzodiazepines, chloral hydrate, haloperidol, lithium, carbamazepine, phenytoin, etc.) and any psychoactive drugs or anti-obesity agents;
• history of major head trauma with loss of consciousness;
• ongoing pregnancy;
• known taste or smell dysfunction;
• a diagnosis of diabetes;
• any known allergies or sensitivity, including to food, vapors or odors;
• pregnant or nursing women,
• history of metalworking, injury with shrapnel or metal slivers, and major surgery;
• history of pacemaker or neurostimulator implantation m) asthma, chronic obstructive pulmonary disease, bronchitis or any other lung disease.