Neural Correlates and Behavioral Impact of Withdrawal-induced Hyperalgesia Among People Who Smoke With and Without Chronic Pain

Inclusion Criteria:

1. History of chronic non-cancer low back pain with duration ≥ 6 months OR no history of chronic pain;
2. age 21-65;
3. smoking of at least 10 cig/day for \> 2 years;
4. have an iPhone or Android smartphone capable of running the EMA software

Exclusion Criteria:

1. pain complaint specifically due to cancer, rheumatoid arthritis, or complex regional pain syndrome;
2. actively taking steps to quit smoking;
3. inability to attend all required experimental sessions;
4. significant health problems, such as chronic hypertension, emphysema, seizure disorder, history of significant heart problems;
5. conditions that would make MRI scanning unsafe (e.g., metal implants, claustrophobia)
6. use of opioids within the past 90 days
7. past year alcohol or substance use disorder
8. positive urine test for illegal drugs (other than marijuana);
9. daily use of alcohol or marijuana;
10. lifetime history of psychotic disorder, or current unstable psychiatric disorder;
11. regular use of non-cigarette tobacco products or electronic cigarettes;
12. major surgery within the past 6 months or planned surgery within the timeframe of the study;
13. breath alcohol level \> 0.0 (participants failing for BAL will be allowed to rescreen once);
14. recently quit smoking for \> 3 days;
15. pregnancy or planning to become pregnant;
16. any factors that at the discretion of the investigators would adversely affect the participant or integrity of the study (e.g., ongoing legal action or disability claim regarding pain, uncontrolled psychiatric disorder, head/neck injury, use of certain medications)