Florida State University
Cannabis use disorder (CUD) and major depressive disorder (MDD) are among the most prevalent psychiatric conditions in the United States, affecting an estimated 20.6 million and 21 million adults respectively. Both disorders are characterized by anhedonia, diminished motivation, and blunted neural reward sensitivity. This shared dysregulated reward-processing may reflect a common prefrontal oscillatory dysfunction, centralized in mesolimbic dopaminergic reward pathways. This proposed project aims to investigate if transcranial alternating current (tACS) can modulate motivational behaviours and neural reward responsivity in participants with MDD and/or CUD during an effortful reward task. The investigators hypothesize that delta transcranial alternating current stimulation will produce a greater neural reward responsivity (RewP), and motivational behaviour during an effortful reward task.
Disrupted reward processing is a transdiagnostic feature that plays a central role in the development, and maintenance of anhedonia in Cannabis Use Disorder (CUD) and Major Depressive Disorder (MDD). Reward positivity (RewP) is an event-related potential (ERP) component derived from electroencephalogram (EEG) data, associated with motivation, reward responsivity and valuation. This neural signature originates in the medial and dorsolateral prefrontal cortexes. In MDD, reduced RewP has been associated with decreased willingness to expend effort for reward. Research of CUD and RewP is scarce, bu…
Inclusion Criteria (General): * Aged between 18 - 55 years old. * Able to provide informed consent * Have normal to corrected vision * Willing to comply with all study procedures and be available for the duration of the study * Speak and understand English. * Negative THC saliva test and alcohol breathalyzer at all lab visits. * Negative UTOX for any substance other than THC. Exclusion Criteria (General): * Mania history (Bipolar I, or current mania). * Psychosis history. * Current suicide intent (score \>4 on C-SRSS, or intent \>0 on SRA) * Current moderate-to-severe SUD or AUD (Except CUD…
The tACS stimulation is briefly turned on and off over the course of 15-30 seconds.
Approximately 20-minutes of delta stimulation (2.5Hz) applied to F3 (returns AF7, FC5, FC1) and AFz (returns Fp1, Fp2, F2). Transcranial Alternating Current Stimulation Device is NeuroConn DC-Stimulator MC.
Approximately 20-minutes of theta stimulation (6Hz) applied to F3 (returns AF7, FC5, FC1) and AFz (returns Fp1, Fp2, F2). Transcranial Alternating Current Stimulation Device is NeuroConn DC-Stimulator MC.