Brain Mechanisms Supporting Cannabis-induced Pain Relief

Inclusion Criteria: * Between 21-65 years old * Currently 30 days cannabis free * Lower back pain for three months or more * Are not taking opioids * If female and of a child bearing potential age, are not pregnant or nursing mothers * Do not have mental or neurological conditions inhibiting sensory/motor functions * Do not have a lifetime history of dependence on cannabis * Do not have a lifetime history of DSM-IV schizophrenia, bipolar disorder, panic disorder, or psychosis * Prior THC-containing cannabis experience within the past two years * Agrees not to use cannabis outside of the study during participation in the study * Agrees not to use opioids or barbiturates during participation in the study * Agrees not to drive a motor vehicle within 4 hours following last use of inhaled cannabis during participation in the study Exclusion Criteria: * Active pulmonary disease * Allergy or past adverse effects or negative past experiences from cannabis * Positive urine drug test for THC, barbiturates, opioids, oxycodone, or methadone * Any significant illness, including cardiovascular disease, diabetes, renal and liver disease. * Any current or history of an immunocompromising disease or condition (such as lupus, psoriasis, multiple sclerosis, etc.) * Any current or history of neurologic conditions, including Parkinson disease, dementia, cognitive impairment, history of seizure disorder, and history of traumatic brain injury/head injury * Any current major psychiatric illness, such as bipolar disorder, major depression, psychosis, substance use disorder, or schizophrenia * Any current or history of suicidal ideation or attempt * Overt sensitivity to thermal stimulation * Resting blood pressure \> 140/90 * Resting heart rate \> 100 beats/minute * Prisoner * Institutionalized * Claustrophobia * MRI contraindications * Participation in any new (within 2 weeks prior or any time after enrollment) pain management procedures during the study period * Known history of vasovagal fainting, syncope, or severe adverse reactions associated with blood draws or needle procedures