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OpenTrials
Completed

NCT Number: NCT03800030

Effect of Cross Frequency tACS on Cognitive Control

Investigation of frequency specific transcranial alternating current stimulation on cognitive control signals in frontal cortex

Completed

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Key information

Conditions

Cognitive Control Executive Function

Age range

18 year–35 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of North Carolina, Chapel Hill

Chapel Hill, North Carolina, 27599, United States

About this study

Previous evidence suggests that there are specific frequency bands associated with different aspects of cognitive control. In specific delta (2-4Hz) and beta (15-30Hz) are associated with increased levels of abstraction for learned rules; and theta (5-8Hz) and gamma (30-50Hz) has been associated with increased set-size or number of learned rules. Here we aim to find causal evidence in support of these previous correlational findings by applying cross-frequency transcranial alternating current stimulation (tACS) in the specific frequency bands previously shown to be task-relevant. In a crossover design, we stimulate subjects with either delta-beta or theta-gamma tACS during performance of a hierarchical cognitive control task that manipulates the level of abstraction and set-size of rules that must be learned in order to make the correct button press.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Between the ages of 18 and 35 years
  • Able to provide informed consent
  • Willing to comply with all study procedures and be available for the duration of the study Speak and understand English

Exclusion criteria

  • Attention Deficit Hyperactivity Disorder (currently under treatment)
  • Neurological disorders and conditions, including, but not limited to:
  • History of epilepsy
  • Seizures (except childhood febrile seizures and electroconvulsive therapy induced seizures) Dementia
  • History of stroke
  • Parkinson's disease
  • Multiple sclerosis
  • Cerebral aneurysm
  • Brain tumors
  • Medical or neurological illness or treatment for a medical disorder that could interfere with study participation (e.g., unstable cardiac disease, malignancy)
  • Prior brain surgery
  • Any brain devices/implants, including cochlear implants and aneurysm clips
  • History or current traumatic brain injury
  • (For females) Pregnancy or breast feeding
  • Personal or family history of mental/psychiatric disorder (e.g., anxiety, major depressive disorder, schizophrenia, etc.)
  • Positive urine test for the following: Marijuana (THC), Cocaine (COC), Phencyclidine (PCP), Amphetamine (AMP), Ecstasy (MDMA), Methamphetamine (Mamp), Opiates (OPI), Oxycodone (OXY), Methadone (MTD), Barbiturates (BAR), Benzodiazepines (BZO), Buprenorphine (BUP), Tricyclic Antidepressants (TCA), Propoxyphene (PPX)
  • Anything that, in the opinion of the investigator, would place the participant at increased risk or preclude the participant's full compliance with or completion of the study

Treatment and study plan

Theta-gamma tACS

Device

NeuroConn technologies, direct current-stimulator plus

Delta-beta tACS

Device

NeuroConn technologies, direct current-stimulator plus

Sham tACS

Device

NeuroConn technologies, direct current-stimulator plus

Primary outcomes

  1. Reaction Time for Trials With High Abstraction Relative to Low Abstraction

    Time frame: through study completion, an average of 3 weeks

    For low abstraction conditions, subjects must memorize a color to button mapping. For high abstraction conditions, subject must make a perceptual judgement on the similarity of two objects based on either texture or shape as cued by a color. The reaction time difference between high and low abstraction conditions was hypothesized to decrease when delta-beta tACS was delivered. As a control for the placebo effect of stimulation, the difference between delta-beta tACS and sham tACS, or placebo, was used for statistical analysis.

  2. Reaction Time for Trials With High Set-size Relative to Low Set-size

    Time frame: through study completion, an average of 3 weeks

    The reaction time difference between high and low set-size conditions was hypothesized to decrease when theta-gamma tACS is delivered. As a control for the placebo effect of stimulation, the difference between theta-gamma tACS and sham tACS, or placebo, was used for statistical analysis.

  3. Delta Phase to Beta Amplitude Coupling Strength

    Time frame: through study completion, an average of 3 weeks

    Delta-beta tACS was hypothesized to increase cross frequency coupling strength (higher value) between the targeted frequency bands. Phase amplitude coupling between delta phase and beta amplitude was calculated for the two minute electrical brain recordings after stimulation. A null distribution was calculated by shuffling the beta amplitude time series relative to the delta phase time series and then calculating coupling strength. The outcome measure is the z-transformed value of the genuine phase amplitude coupling relative to the null distribution.

  4. Theta Phase to Gamma Amplitude Coupling Strength

    Time frame: through study completion, an average of 3 weeks

    Theta-gamma tACS was hypothesized to increase cross frequency coupling strength (higher value) between the targeted frequency bands. Phase amplitude coupling between theta phase and gamma amplitude was calculated for the two minute electrical brain recordings after stimulation. A null distribution was calculated by shuffling the gamma amplitude time series relative to the theta phase time series and then calculating coupling strength. The outcome measure is the z-transformed value of the genuine phase amplitude coupling relative to the null distribution.

  5. Percent Correct for Trials With High Abstraction Relative to Low Abstraction

    Time frame: through study completion, an average of 3 weeks

    For low abstraction conditions, subjects must memorize a color to button mapping. For high abstraction conditions, subject must make a perceptual judgement on the similarity of two objects based on either texture or shape as cued by a color. The accuracy difference between high and low abstraction conditions was hypothesized to decrease when delta-beta tACS was delivered. As a control for the placebo effect of stimulation, the difference between delta-beta tACS and sham tACS, or placebo, was used for statistical analysis.

  6. Percent Correct for Trials With High Set-size Relative to Low Set-size

    Time frame: through study completion, an average of 3 weeks

    The accuracy difference between high and low set-size conditions was hypothesized to decrease when theta-gamma tACS is delivered. As a control for the placebo effect of stimulation, the difference between theta-gamma tACS and sham tACS, or placebo, was used for statistical analysis.

Sponsors and collaborators

Lead sponsor

University of North Carolina, Chapel Hill

Other

Collaborators

  • National Institute of Mental Health (NIMH)

Registry information

Official study title

A Pilot Study Investigating the Effects of Cross Frequency Transcranial Alternating Current Stimulation on Cortical Oscillations Underlying Cognition

Important dates

Study start
2018
Primary completion
2019
Study completion
2019
First posted
Jan 10, 2019
Registry last updated
May 18, 2020

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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