Pilot fMRI Studies of Aging-Related Effects of THC

Inclusion Criteria:

* 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 the study protocol.

Exclusion Criteria:

* Current marijuana tolerance, desire to cut down, or cravings to use during periods of abstinence.
* 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
* 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
* Hearing loss such that subject cannot hear sounds at the levels (dB) or pitches (Hz) to be used in the study
* Significant pain and/or reduced mobility in the arms