An investigation of the initial neural responses to tobacco vs fruity flavored electronic cigarette odor cues among cigarette smokers
Restricted (Penn State Only)
- Author:
- King, Erin
- Graduate Program:
- Neuroscience (MS)
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- March 12, 2024
- Committee Members:
- Andrea Hobkirk, Thesis Advisor/Co-Advisor
Jennifer E Nyland, Committee Member
Alistair Barber, Program Head/Chair
Qing X Yang, Committee Member - Keywords:
- Tobacco
electronic cigarettes
cue reactivity
nicotine
fMRI
associative learning
craving
food
olfaction
harm reduction
odor cues - Abstract:
- Tobacco Use is the leading preventable cause of death in the United States. Chronic smokers can use electronic cigarettes (E-CIGS) as a harm reduction tool. E-CIGS provide less carcinogens while still supplying nicotine, allowing smokers to avoid nicotine withdrawal. Unlike cigarettes, E-CIGS come in a variety of flavor options and fruity and dessert type flavors are the most popular among E-CIG users of all ages. It is still unclear how non-tobacco flavor additives might affect cigarette smokers’ ability to switch to E-CIGS for harm reduction. Flavor is relevant because most cigarette users have strong, conditioned associations between the rewarding effects of nicotine and cigarette taste and smell. This is reliably observed as cue reactivity, where nicotine dependent individuals show strong responses to drug cues which can include alterations in interoceptive awareness, neural activation, and associative learning. Our study aimed to compare initial neural responses to the tobacco E-CIG odor cue and strawberry-vanilla (food) E-CIG odor cue, and if odor cue brain reactivity was associated with tobacco use characteristics, cigarette craving, and subjective odor ratings. Regular cigarette smokers (n=19) attended a laboratory visit where they completed functional magnetic resonance imaging (fMRI) while smelling four odors (tobacco e-liquid, strawberry-vanilla e-liquid, rose, lavender) during an odd-ball cue-reactivity odor task. We found increased average BOLD activation to the tobacco E-CIG cue compared to the strawberry-vanilla in brain regions involved in cue-reactivity, salience, and reward such as the hippocampus, amygdala, insula, putamen, globus pallidus, brain stem and cerebellum. We found increased BOLD activation to the strawberry-vanilla E-CIG odor cue in the anterior cingulate cortex and medial prefrontal cortex (mPFC) that are typically involved in food processing. We found that increased tobacco familiarity, increased craving amount, increased cigarettes per day (CPD), and years of use were significantly associated with increased BOLD activation to the tobacco E-CIG odor. The results suggest that the tobacco E-CIG odor acts as a cigarette cue while the strawberry odor acts as a food cue. The findings lend support for the hypothesis that tobacco-flavored E-CIGs may work as a better harm reduction tool than a fruity-flavored E-CIG by satisfying conditioned odor and taste experiences during smoking.