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NCT Number: NCT05923606

Modulation of Brain Oscillations Underlying Working Memory

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.

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Key information

Conditions

Working Memory

Age range

18 year–35 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Martinos Center for Biomedical Imaging

Charlestown, Massachusetts, 02129, United States

Location status: Recruiting

Location contact

Alexandra O'Neill, B.S.

CONTACT

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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)

Treatment and study plan

Active tACS

Device

Active tACS will be administered over the left dorsolateral prefrontal cortex for approximately 25 minutes.

Placebo tACS

Device

Placebo tACS will be administered over the left dorsolateral prefrontal cortex for approximately 25 minutes.

Primary outcomes

  1. Working memory accuracy

    Time frame: 2 hours

    Accuracy of working memory retrieval during a Delayed Match-to-Sample task will be assessed before and during tACS interventions

  2. Working memory accuracy under interference

    Time frame: 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.

  3. Theta-gamma cross-frequency coupling

    Time frame: 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.

  4. Fronto-parietal theta phase synchronization

    Time frame: 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.

Study contacts

Contact information is provided by the study sponsor or research team.

Allyson Smith, B.S.

CONTACT

[email protected]

(617) 726-1040

Hamdi Eryilmaz, Ph.D.

CONTACT

[email protected]

(617) 643-7462

Sponsors and collaborators

Lead sponsor

Massachusetts General Hospital

Other

Registry information

Official study title

State-dependent Modulation of Interactions of Theta and Gamma Rhythms in Working Memory

Important dates

Study start
2024
Primary completion
2026
Study completion
2027
First posted
Jun 28, 2023
Registry last updated
Feb 9, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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