Traveling-wave Transcranial Electric Stimulation

Study Overview
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Brief Summary
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This study will assess the impact of traveling wave transcranial alternating current stimulation (tACS) on working memory performance in adults.

Detailed Description
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Transcranial alternating current stimulation (tACS) can non-invasively alter neuroelectric activity in the brain by applying weak time-varying electric currents via the scalp. Complex patterns of electric brain activity can take the form of traveling waves - spatially coherent brain rhythms that gradually propagate through the neocortex. Traveling waves are crucial for the temporal coordination of informational flow in the brain. Using the novel traveling-wave transcranial alternating current stimulation (tACS) approach, the investigators will explore the effects of frontal-to-parietal and parietal-to-frontal traveling waves on working memory performance and brain electrophysiology in adults.

Official Title
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Precision Transcranial Electric Stimulation for the Therapy of Cognitive Impairment

Conditions
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Working Memory

Intervention / Treatment
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* Device: Transcranial alternating current stimulation (tACS)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age between 18 and 45 years old. Confident level of English language. Exclusion Criteria: History or evidence of chronic neurological or mental disorder. Metal or electric implant in the head, neck, or chest area. History of head injuries with loss of consciousness. Any acute or chronic medical condition that requires ongoing pharmacological treatment. Pregnancy or breast-feeding. Alcohol or drug addiction.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Frontoparietal Slow Theta Stimulation<br>Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces frontal-to-parietal traveling wave at the frequency of 4 Hz with the intensity of up to 2 mA and duration up to 20 min. | Device: Transcranial alternating current stimulation (tACS)<br>* Non-invasive, multi-electrode transcranial alternating current stimulation (tACS) over frontal and parietal brain areas.<br>|
| Experimental: Frontoparietal Fast Theta Stimulation<br>Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces frontal-to-parietal traveling wave at the frequency of 7 Hz with the intensity of up to 2 mA and duration up to 20 min. | Device: Transcranial alternating current stimulation (tACS)<br>* Non-invasive, multi-electrode transcranial alternating current stimulation (tACS) over frontal and parietal brain areas.<br>|
| Experimental: Parietofrontal Slow Theta Stimulation<br>Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces parietal-to-frontal traveling wave at the frequency of 4 Hz with the intensity of up to 2 mA and duration up to 20 min. | Device: Transcranial alternating current stimulation (tACS)<br>* Non-invasive, multi-electrode transcranial alternating current stimulation (tACS) over frontal and parietal brain areas.<br>|
| Experimental: Parietofrontal Fast Theta Stimulation<br>Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces parietal-to-frontal traveling wave at the frequency of 7 Hz with the intensity of up to 2 mA and duration up to 20 min. | Device: Transcranial alternating current stimulation (tACS)<br>* Non-invasive, multi-electrode transcranial alternating current stimulation (tACS) over frontal and parietal brain areas.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in working memory performance | Changes in working memory performance (% of correct responses) as measured with the standardized N-back working memory task during active stimulation relative to pre-stimulation performance. | Immediate effect during stimulation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in reaction time | Changes in reaction time (milliseconds) as measured using the standardized N-back working memory task during active stimulation relative to pre-stimulation performance. | Immediate effect during stimulation | 
| Changes in electroencephalographic (EEG) connectivity | Changes in electroencephalographic (EEG) connectivity in theta band (in normalized units) after transcranial electric stimulation relative to pre-stimulation periods. | Five minutes post-stimulation |