Measuring Neuroadaptations in Response to Very Low Nicotine Content Cigarettes

In a double-blind, randomized controlled trial, dependent smokers will be randomized to a 6-week very low nicotine content (VLNC) cigarette condition (N=50) or a 6-week normal nicotine content cigarette control condition (NNC; N=25). Participants will undergo functional magnetic resonance imaging (fMRI) scans at baseline and 6-weeks to investigate the nicotine-related modulation of brain circuitry involved in incentive salience valuation and executive control. Imaging tasks will engage the incentive salience of smoking cues and non-smoking rewards and executive control functions to identify changes in functional activity within, and effective connectivity between, known salience and executive control brain circuitry. A novel fMRI task using specialized odor presentation equipment and fMRI sequences will assess neural cue reactivity to smoke odors.

Inclusion criteria

• 21-60 years old
• Smoke >5 cigarettes per day
• >1 year of daily smoking
• No quit attempt in prior month and not planning to quit smoking within next 3 months
• Able to understand and consent to study procedures
• High school or lower educational attainment or annual household income < $50,000
• Plan to live in local area next 3 months
• Women not pregnant or nursing and taking steps to avoid pregnancy
• Able to read and write in English
• Access to computer with internet service that allows for Zoom

Exclusion criteria

• Use of non-cigarette tobacco products in the past 7 days
• Use of illicit substances more than once a week in the past 3 months (excluding marijuana)
• Current alcohol abuse impairing participation
• MRI safety contraindications (e.g., metal implants, claustrophobia)
• Unstable or significant medical conditions (e.g., chronic obstructive pulmonary disorder, coronary heart disease)
• Major neurological conditions or brain trauma
• Major surgeries planned in next 3 months
• Use of smoking cessation medication in prior month (e.g., varenicline, patch)
• Uncontrolled serious mental illness, suicidality, or inpatient psychiatric hospitalization in the past 6 months
• Unwillingness to provide urine samples
• Unwilling to smoke study assigned cigarettes for the remainder of the trial
• Plans to move or take extended travel out of the area in the next 3 months
• Any other condition or situation that would, in the investigator's opinion, make it unlikely that the participant could comply with the study protocol
• Self-reported color blindness
• Left-handedness
• Smell dysfunction as determined via standardized assessment