Effect of Cross Frequency tACS on Cognitive Control

Executive Function Clinical Trial

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT03800030
• Other study ID #: 18-0003
• Secondary ID: R01MH101547
• Status: Completed
• Phase: N/A
• Start date: October 7, 2018
• Est. completion date: July 25, 2019

Study information

• Verified date: September 2019
• Source: University of North Carolina, Chapel Hill
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

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

Description:

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 26
• Est. completion date: July 25, 2019
• Est. primary completion date: July 25, 2019
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 35 Years

Eligibility

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

Related Conditions & MeSH terms

• Cognitive Control
• Executive Function

Intervention

Device:
• Theta-gamma tACS
NeuroConn technologies, direct current-stimulator plus
• Delta-beta tACS
NeuroConn technologies, direct current-stimulator plus
• Sham tACS
NeuroConn technologies, direct current-stimulator plus

Locations

Country	Name	City	State
United States	University of North Carolina, Chapel Hill	Chapel Hill	North Carolina

Sponsors (2)

Lead Sponsor	Collaborator
University of North Carolina, Chapel Hill	National Institute of Mental Health (NIMH)

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Reaction Time for Trials With High Abstraction Relative to Low Abstraction	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.	through study completion, an average of 3 weeks
Primary	Reaction Time for Trials With High Set-size Relative to Low Set-size	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.	through study completion, an average of 3 weeks
Primary	Delta Phase to Beta Amplitude Coupling Strength	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.	through study completion, an average of 3 weeks
Primary	Theta Phase to Gamma Amplitude Coupling Strength	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.	through study completion, an average of 3 weeks
Primary	Percent Correct for Trials With High Abstraction Relative to Low Abstraction	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.	through study completion, an average of 3 weeks
Primary	Percent Correct for Trials With High Set-size Relative to Low Set-size	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.	through study completion, an average of 3 weeks