NCT06634771

Flexibility, Alcohol Misuse, and Excitation

Frontal E/I Balance Mediation of tACS Effects on Behavioral Flexibility

• Status: Terminated
• Phase: N/A
• Study type: Interventional
• Enrollment: 7 (actual)
• Sponsor: University of North Carolina, Chapel Hill · Academic / Other
• Sex: All
• Age: 22 Years – 50 Years
• Healthy volunteers: Accepted

Summary

The goal of this study is to learn whether a single non-invasive brain stimulation alpha-transcranial alternating current stimulation (alpha-tACS) session changes measures of excitability in the prefrontal cortex. It will also learn whether these changes predict differences in habitual action selection in a laboratory task and whether the effects depend on alcohol use history. The main questions it aims to answer are: Does alpha-tACS reduce habitual action selection by reducing excitability in the prefrontal cortex? Is alpha-tACS most effective in reducing habitual action selection in hazardous drinkers who engaged in binge-drinking during adolescence? Researchers will compare alpha-tACS to sham stimulation to see if alpha-tACS changes habitual action selection by changing prefrontal excitability. Participants will: Visit the lab for behavioral training Visit the imaging center for an MRI session Visit the lab to receive alpha-tACS or sham stimulation during behavioral testing and undergo EEG recordings before and after stimulation Visit the imaging center for a repeat MRI session Provide a small sample of blood from a finger-prick in the first and last visits.

Detailed description

This study is designed to probe the role of the balance between excitatory (E) and inhibitory (I) signaling (E/I) in key nodes of control circuitry in mediating the relationship between alcohol misuse and inflexible behavior. In addition, the investigators aim to determine whether adolescent binge alcohol exposure amplifies the effects of binge exposure in adulthood. The investigators will accomplish this goal via a single multi-session study. Participants (n=66) will comprise three groups: adults self-reporting high risk drinking \[World Health Organization (WHO) risk levels 2, 3, or 4\], with (n=22) or without (n=22) a history of adolescent alcohol misuse (AIE), and lifetime low risk drinking adults (WHO risk levels 0 or 1; n=22). Design: a 3-session study that includes an initial screening session and behavioral training (Session 1), behavioral testing and a magnetic resonance imaging (MRI) scan session (Session 2), bifrontal 10Hz-transcranial alternating current stimulation (tACS; true or sham) during behavioral testing with pre- and post-electroencephalogram (EEG) recording in a resting-state, followed by a second MRI scan session (Session 3). The investigators predict that adolescent and adult binge history will have interacting effects on E/I balance indices derived from EEG and magnetic resonance spectroscopy (MRS) and on behavioral flexibility measured in the Hidden Association between Images Task (HABIT) Test and that E/I balance indices will mediate the relationship between alcohol misuse and behavioral flexibility. The investigators also propose to test a causal relationship between E/I balance and behavioral flexibility by testing whether 10Hz-tACS to bilateral dorsolateral prefrontal cortex (dlPFC) alters habitual action selection in the HABIT Test in proportion to its effects on the dlPFC 1/f EEG slope and/or the MRS-derived gamma-amino-butyric acid (GABA)/glutamate+glutamine (Glx) ratio. The investigators predict that changes in indices of E/I balance induced by tACS will inversely associate with changes in habitual response selection. The investigators will collect a small amount of blood from a finger prick in Sessions 1 and 3 will use the collected dried blood spots to measure inflammatory markers.

Conditions

• Behavioral Flexibility
• Healthy Volunteers
• High Risk Alcohol Use

Interventions

Type	Name	Description
OTHER	10 Hz transcranial alternating current stimulation (tACS)	10 Hz bi-frontal tACS: Alternating current stimulation is delivered by an XCSITE 100 device (Pulvinar Neuro, Chapel Hill, NC), through three conductive carbon-rubber electrodes. Electrodes are placed over the apex of the head (Cz) and the prefrontal cortex bilaterally (F3 and F4). Stimulation is delivered during the second half of the HABIT Test session. Stimulation parameters: 2mA peak-to-peak 10Hz sine-wave flanked by 10 second linear envelope ramps in and out for a total duration of 30 min and 20 seconds.
OTHER	sham transcranial alternating current stimulation (tACS)	Sham tACS: The procedure for sham stimulation will be identical, but it will last for 2 minutes instead of 30 minutes.

Timeline

• Start date: 2024-07-18
• Primary completion: 2025-01-24
• Completion: 2025-01-24
• First posted: 2024-10-10
• Last updated: 2026-03-27
• Results posted: 2026-03-27

Locations

1 site across 1 country: United States