State-dependent Modulation of Interactions of Theta and Gamma Rhythms in Working Memory
Massachusetts General Hospital
Summary
This study will use novel transcranial alternating current stimulation (tACS) protocols and electroencephalography (EEG) to modulate and measure brain oscillations that underlie working memory. tACS is a noninvasive method used to modulate the timing and patterns of brain rhythms via weak electric currents passed through electrodes on the scalp.
Description
In this study, healthy adult individuals will perform a spatial working memory task as investigators record scalp EEG before and immediately after undergoing transcranial alternating current stimulation (tACS). Each participant will complete four tACS sessions in randomized order: 1) theta-nested gamma tACS applied during active task periods, 2) theta-nested gamma tACS applied during passive (rest) periods, 3) gamma stimulation applied in phase with ongoing theta oscillations, and 4) placebo tACS. The different stimulation protocols will take place on different days. Therefore, participants wi…
Eligibility
- Age range
- 18–35 years
- Sex
- All
- Healthy volunteers
- Yes
Inclusion Criteria: * Able to provide informed consent * Fluent in English. Exclusion Criteria: * History of a neurological/psychiatric disorder * Current use of psychotropic medications * Current use of substances and drugs that were shown to affect tES (transcranial electrical stimulation) efficacy (dopamine altering drugs, nicotine, NMDA (N-methyl-D-aspartate) antagonists/agonists, sodium/calcium channel blockers, norepinephrine reuptake inhibitors, GABAergic modulators and selective serotonin reuptake inhibitors) * Contraindications for tACS (e.g., history of seizures, metallic implants…
Interventions
- DeviceActive tACS
Active tACS will be administered over the left dorsolateral prefrontal cortex for approximately 25 minutes.
- DevicePlacebo tACS
Placebo tACS will be administered over the left dorsolateral prefrontal cortex for approximately 25 minutes.
Location
- Martinos Center for Biomedical ImagingCharlestown, Massachusetts