Inclusion Criteria:  18-55 years old Right handed CNB use within past 2 years and felt "high" when used Able to read, speak, and understand English Able and willing to provide written informed consent, and willing to commit to study protocol.  Exclusion Criteria:  Current marijuana tolerance, desire to cut down, or cravings to sue during periods of abstinence. Strongly left-handed Positive screen for drug or alcohol (except CNB) on test day will result in rescheduling the appointment History of adverse effects with CNB CNB users who are abstaining Report of any psychotic disorder in a first degree relative IQ < 80 on the Wechsler Abbreviated Scale of Intelligence Inability to comprehend written instructions using the WRAT-4 reading achievement test Pregnant, breastfeeding, and ineffective birth control methods. Unable or unsafe to have an MRI Serious medical, neuro-ophthalmological, or neurological illness (e.g. cancer, seizure disorders, encephalopathy History of head trauma with loss of consciousness > 30 minutes or concussion lasting 30 days. Focal brain lesion seen on structural MRI Any medical/neurological condition that could compromise neurocognitive performance (e.g. epilepsy, multiple sclerosis, fetal alcohol syndrome). Anyone deemed unsafe to study personnel for any reason