Working Memory
Conditions
Keywords
Working memory, Attention, Theta oscillations, Transcranial Alternating Current Stimulation
Brief 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.
Detailed 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 will be expected to attend 4 in-person study visits at the Martinos Center for Biomedical Imaging in Charlestown, Massachusetts.
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.
Sponsors
Massachusetts General Hospital
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 35 Years
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 in the head or neck, implanted brain stimulators, vagus nerve stimulators, pacemakers, pregnancy)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Working memory accuracy | 2 hours | Accuracy of working memory retrieval during a Delayed Match-to-Sample task will be assessed before and during tACS interventions |
| Working memory accuracy under interference | 2 hours | Accuracy of working memory retrieval during interference conditions of a Delayed Match-to-Sample task will be assessed before and during tACS interventions. |
| Theta-gamma cross-frequency coupling | 2 hours | Cross-frequency coupling between theta band phase and gamma band amplitude will be calculated using the EEG data collected while subjects perform the Delayed Match-to-Sample task before and after tACS interventions. |
| Fronto-parietal theta phase synchronization | 2 hours | Phase synchronization in the theta band between frontal and parietal brain regions will be calculated using the EEG data collected while subjects perform the Delayed Match-to-Sample task before and after the tACS interventions. |
Countries
United States
Contacts
CONTACTAllyson Smith, B.S.
CONTACTHamdi Eryilmaz, Ph.D.
PRINCIPAL_INVESTIGATORHamdi Eryilmaz, Ph.D.
Massachusetts General Hospital
Outcome results
None listed