Examining the Effects of Cytisinicline on Neural Substrates of Cigarette Cue-reactivity

Inclusion Criteria: 1. be between the ages of 18 and 65 and provide informed consent; 2. smoke 5 or more combustible cigarettes per day; 3. not seeking treatment for smoking; Exclusion Criteria: 1. current use of other smoking cessation aid (bupropion, varenicline, nortriptyline, NRT); 2. more than 3 months of smoking abstinence in past year; 3. use of non-cigarette tobacco product (pipe tobacco, cigars, smokeless tobacco, hookah) or electronic cigarettes more than 5 times in the 28-days prior to enrollment; 4. current use of psychoactive drug (excluding cannabis), as determined by urine toxicology; 5. current (past 12-month) DSM-5 diagnosis of substance use disorder for any substances other than tobacco and mild cannabis or mild-to-moderate alcohol use disorders; 6. lifetime history of psychotic disorders, bipolar disorders, or major depression with suicidal ideation; 7. current suicidal ideation or lifetime history of suicide attempt; 8. serious medical illness within past 3 months, including recent history of acute myocardial infarction, unstable angina, stroke, cerebrovascular incident, or hospitalization for congestive heart failure; 9. medical condition that may interfere with safe study participation; 10. renal impairment defined as a creatinine clearance (CrCl) greater than 60 mL/min (estimated with the Cockroft-Gault equation); 11. exceed Grade 2 laboratory abnormalities, based on FDA Guidance Document "Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers Enrolled in Preventive Vaccine Clinical Trials"; 12. uncontrolled hypertension (blood pressure ≥160/100 mmHg); 13. abnormal electrocardiogram; 14. non-removable ferromagnetic object in body; 15. claustrophobia; 16. serious head injury or period of unconsciousness (more than 30 minutes); 17. more than 250lbs; 18. Be pregnant, nursing, or planning to become pregnant while taking part in the study; and must agree to one of the following methods of birth control (if female), unless she or partner are surgically sterile: * Oral contraceptives * Contraceptive sponge * Patch * Double barrier * Intrauterine contraceptive device * Etonogestrel implant * Medroxyprogesterone acetate contraceptive injection * Hormonal vaginal contraceptive ring * Complete abstinence from sexual intercourse; 19. have experienced adverse effects to varenicline; 20. have an intense fear of needles or have had an adverse reaction to needle puncture.