Neural Basis of Eating Behavior in Abstinent Smokers

Tobacco use and obesity are the two leading causes of preventable deaths. Because these two
behaviors share common brain reward mechanisms, reducing one behavior often leads to
increases in the other behavior. Behavioral Economic and Incentive Salience models shed much
light on this clinical problem. Smoking cessation produces reward dysregulation that can
alter the motivational salience of other reinforcers, particularly food. After stopping
smoking, smokers increase between-meal snacking, especially foods high in fat and sugar.
Increases in caloric intake occur within days of quitting smoking, and are clinically
significant. The investigators have also shown that smoking cessation produces working memory
deficits and reduces activity in the brain's cognitive control circuits, making it even more
difficult to exert self-control over temptations to eat highly rewarding foods. Thus, smokers
have a double challenge: food becomes more salient and reinforcing at a time when their
neurocognitive resources are compromised.

Neuroimaging can identify mechanisms underlying behavior change beyond self-report and
behavioral measures. The proposed functional magnetic resonance imaging (fMRI) study breaks
new ground by integrating concepts and tools from the fields of behavioral economics and
cognitive neuroscience to accelerate the study of mechanisms underlying PCWG. The
investigators will use a previously validated within-subject crossover neuroimaging study
design to examine changes in working memory, food salience (cue-induced craving), and food
reinforcement processes in the brain after 4 days of smoking cessation (vs. smoking as
usual). A non-smoker control group will provide insight into baseline differences from
smokers (abstinent and satiated). Caloric intake, the primary outcome, will be assessed using
24-hr. food recalls during each study period. The investigators will assess three parallel
pathways including: working memory, food cue reactivity, and food reinforcement at the neural
and behavioral levels.

This study will provide new insights about how the brain can constrain or promote the ability
of smokers to prevent post cessation weight gain (PCWG) and lead to new interventions that
integrate neural and behavioral framework. Support for our predictions would inform testing
of novel approaches to prevent PCWG, such as computerized neurocognitive exercise training to
increase DLPFC activity and shift activity away from reward sensitive brain networks.

Inclusion Criteria

Male and female participants who are between 18 and 45 years of age.

Smoking group - 80 treatment-seeking smokers who self-report smoking at least 10 cigarettes
(menthol and/or non-menthol) per day for at least the last 6 months. Smoking status will be
confirmed by CO greater than or equal to 8 parts per million (ppm) at the Intake Visit.

Non-smoking group - 30 individuals reporting fewer than 100 lifetime cigarettes and not
even a puff of a cigarette for a minimum of 2 years. Smoking status of non-smokers will be
confirmed by CO less than 5ppm. They will be matched to the smoker group on age, sex, and
education.

Plan to live in the area for the duration of the study (i.e. ~8 weeks/2 months).

Capable of giving written informed consent, which includes compliance with the requirements
and restrictions listed in the combined consent and HIPAA form.

Smokers who wish to make a permanent quit attempt in the next 1-2 months
(treatment-seeking), because our prior work suggests that motivated subjects are more
sensitive to medication effects on smoking behavior. Using a scale from 0 to 100 (100,
being extremely interested), subjects must rate their interest in quitting smoking within
the next 1-2 months greater than 50.

Able to communicate fluently in English (i.e. speaking, writing, and reading).

Exclusion Criteria

Subjects who present and/or self-report with the following criteria will not be eligible to
participate in the study:

Smoking Behavior

1. Regular use of nicotine-containing products other than cigarettes (e.g. chewing
tobacco, snuff, snus, cigars, e-cigs, etc.). Participants agreeing to abstain from
using nicotine- containing products other than cigarettes will be considered eligible.

2. Current enrollment or plans to enroll in another research and/or smoking cessation
program over the duration of the study (i.e. ~8 weeks/2 months).

3. Anticipated use (within the next ~8 weeks/2 months) of any nicotine substitutes and/or
smoking cessation treatments/medications unless provided through the study.

4. Provide a CO breath test reading less than 8 ppm at Intake Visit (smokers) or greater
than 5ppm at intake visit (non-smokers).

Alcohol and Drug

1. History of substance abuse (other than nicotine) in the past 12 months and/or
currently receiving medical treatment for substance abuse. Counseling and support
groups (e.g. Alcoholics Anonymous and Narcotics Anonymous) will not be considered
medical treatment for the purposes of this protocol.

2. Current alcohol consumption that exceeds 25 standard drinks/week.

3. Breath alcohol reading (BrAC) greater than .000 at the Intake Visit.

4. A positive urine drug screen (UDS) for cocaine, opiates, amphetamines,
methamphetamines, phencyclidine (PCP), ecstasy (MDMA), barbiturates, benzodiazepines,
methadone, and/or oxycodone at the Intake Visit.

Medical

1. Women who are pregnant, breast feeding, or planning a pregnancy over the duration of
the study period. Women must agree to use an adequate form of contraception or abstain
from sexual intercourse for the duration of the study.

2. Current treatment of cancer or diagnosed with cancer (except basal or squamous-cell
carcinoma not treated with chemotherapy and/or radiation) in the past 6 months.

3. Poorly controlled, brittle, or pump-dependent Type I diabetes.

4. Current peptic ulcer bleeding.

5. Active hepatitis or poorly controlled kidney and/or liver disease.

6. Serious or unstable disease within the past 6 months. Notable diseases will be
evaluated on a case-by-case basis by the Principal Investigator and/or the Study
Physician.

7. Any impairment including, but not limited to, visual, physical, and/or neurological
impairments preventing proper completion of the study procedures. Notable impairments
will be evaluated on a case-by-case basis by the Principal Investigator and/or the
Study Physician.

8. Applicable food allergies or disorders:

- Galactosemia a

- Notable milk allergy (lactose intolerant participants may proceed unless they
experience severe symptoms) b

- Notable soy allergy c

- Peanut allergy d a,b,c Boost® Original Very Vanilla Nutritional Shake: Contains
milk and soy ingredients. Suitable for Lactose Intolerance.

1. b,c,d M&M's® (Milk Chocolate): Contains milk and soy ingredients (MAY
CONTAIN PEANUTS) Lay's® Classic Potato Chips (Gluten Free): Potatoes,
vegetable oil, and salt

Psychiatric

1. Current diagnosis of major depression. Subjects with a history of major depression, in
remission for 6 months or longer (may be stable on antidepressant medications), are
eligible.

2. Lifetime history of a suicide attempt.

3. Lifetime history of schizophrenia, psychosis, and/or bipolar disorder.

4. Current diagnosis of Attention Deficit/Hyperactivity Disorder (ADHD).

5. Current diagnosis of bulimia, anorexia nervosa or binge eating.

Medication

Current use or recent discontinuation (within the last 14 days) of:

1. Smoking cessation medication (e.g., Zyban, Wellbutrin, Wellbutrin SR, Chantix).

2. Benzodiazepines and/or Barbiturates.

3. Anti-psychotic medications.

4. Prescription stimulants (e.g., Provigil, Ritalin, Adderall).

5. Systemic steroids.

6. Medications for the use of addiction treatment.

Current use of:

7. Nicotine replacement therapy (NRT).

8. Heart medications such as digoxin, quinidine, and nitroglycerin.

Daily use of:

9. Opiate-containing medications for chronic pain.

10. Inhaled corticosteroids.

Subjects will be instructed to refrain from using any study-prohibited drugs/medications
(both recreational and prescription) throughout their participation in the study. After
final eligibility is confirmed, subjects who report taking contraindicated medication(s)
over the course of the study period may only remain eligible if the Study Physician and
Principal Investigator determine that the contraindicated medication(s) do/did not
significantly impact the study design, data quality, and/or subject safety and welfare.
Subjects are permitted to take necessary prescription medications not included within the
exclusion list during the study.

General Exclusion

1. Past, current, anticipated, or pending enrollment in another research program over the
study period that could potentially impact subject safety, study data, and/or the
study design as determined by the Principal Investigator and/or Study Physician.

2. Participation in a dietary program within the past 30 days.

3. Any medical condition, illness, disorder, adverse event (AE), or concomitant
medication that could compromise participant safety or significantly impact study
performance as determined by the Principal Investigator and/or Study Physician.
Subjects may be deemed ineligible for any of the aforementioned reasons at any point
throughout the study, as well as during the initial telephone screen.

4. Significant non-compliance with protocol and/or study design as determined by the
Principal Investigator and/or Study Physician. Subjects may be deemed ineligible at
any point throughout the study.

5. Low or borderline intellectual functioning - determined by receiving a score of less
than 85 on the Shipley Institute of Living Scale (SILS), which correlates with the
Wechsler Adult Intelligence Scale-Revised (WAIS-R) Estimated IQ Test.

fMRI Exclusion Criteria

1. History of claustrophobia.

2. Being left-handed.

3. Lifetime history of stroke.

4. Having a cochlear implant or wearing bilateral hearing aids.

5. History of notable head trauma. Although notable head trauma is typically defined as
being knocked unconscious for a period of three minutes or longer, notable head trauma
will be evaluated on a case-by-case basis by the appropriate personnel prior to an
eligibility decision, considering exceptions can be made based on the nature and
severity of the trauma.

6. History of brain or spinal tumor.

7. Pacemakers, certain metallic implants or objects, or presence of metal in the eye as
contraindicated for MRI.

8. Any circumstances (e.g., exclusionary metal implants, certain dental work, and/or
physical impairments) and/or conditions that may interfere with MRI and MRI-related
study visit procedures. All potential exclusionary circumstances and/or conditions
will be evaluated on a case-by-case basis by the appropriate personnel prior to an
eligibility decision.

9. History of gunshot wounds. Injuries from BB guns will be evaluated on a case-by-case
basis by the appropriate personnel prior to an eligibility decision.

10. History of epilepsy and/or recurrent or uncontrolled seizures.

11. Weight greater than 250 lbs at Intake Visit or self-reported at phone screen. If a
participant weighs less than or equal to 250 lbs at Intake, but presents with a weight
greater than 250 lbs at either Scan 1 and/or Scan 2, the participant may be permitted
to proceed with the scan as long as the participant's weight does not exceed 300 lbs.

12. A positive urine drug screen (UDS) for cocaine, opiates, amphetamines,
methamphetamines, phencyclidine (PCP), ecstasy (MDMA), barbiturates, benzodiazepines,
methadone, and/or oxycodone at intake or either Scan Visit.

13. A BrAC greater than 0.000 at intake or either Scan Visit.