Modulation of Spontaneous Cortical Activity by tDCS: BRAIN Initiative I

Not Applicable

Completed

Conditions: Brain Function

Interventions: Device: transcranial direct-current stimulation (tDCS)

Registration Number: NCT03672747

Lead Sponsor: University of Nebraska

Brief Summary: This study will determine whether transcranial direct current stimulation (tDCS) can be used alter the amplitude of spontaneous neural activity, and thereby modulate cognitive function in healthy adults

Detailed Description: An emerging neurological tool, called transcranial Direct Current Stimulation (tDCS), has recently been shown to safely and effectively enhance cognition in healthy individuals, as well as reduce key symptomatology in disorders such as stroke and depression, with only negligible side effects. tDCS delivers low-amplitude current to the scalp using small electrodes and part of this current passes through the skull and modulates neural activity in the underlying brain region. How this tiny amount of electric current acts to improve cognitive function and reduce symptoms (e.g., motor impairments in stroke patients with a lesion in motor brain areas) is currently unknown, although many investigators across the world are now working on this problem. Magnetoencephalography (MEG) offers a unique view of neural function, as it can delineate changes in active brain regions with excellent temporal resolution (\< 1 ms) and high spatial accuracy (2-3 mm). MEG non-invasively measures the magnetic fields that emanate from active neocortical cells. The potential of the MEG technique to precisely monitor the neural effects of tDCS shows extreme promise, but to date the method has been rarely utilized in this area.

Under this protocol, Modulation of Spontaneous Cortical Activity by tDCS: BRAIN Initiative I, approximately 124 participants will provide written informed consent, undergo cognitive and behavioral testing and a structural MRI during a single visit, and then return several weeks later (2-4 weeks) to complete a short tDCS session followed by a MEG recording (i.e., after tDCS). Most participants will return for two more visits, each separated by 2-4 weeks, that include a tDCS session followed by a MEG recording (i.e., 4 total visits). The three tDCS-MEG visits will be identical except that the nature of the stimulation (e.g., location, amplitude, direction/polarity) will be different.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 133

Inclusion Criteria

Informed consent obtained from the participant.
Age: 19-35 years of age at enrollment or 55-72 years of age at enrollment.
Gender: males and females included.
Right-handed based on the Edinburgh Handedness Inventory
Cognitive functioning: Intelligent Quotient (IQ) of 85 - 115 on the Wechsler Adult Intelligence Scale-Revised
Ability to complete the questionnaires in English, as not all the neuropsychological tests and questionnaires have been validated in other languages.

Exclusion Criteria

Current use of the following medications: psychotropic medications or other medications with significant CNS effects (e.g., antipsychotics, psychostimulants, anticonvulsants, alpha-agonists, adrenergic blockers, lithium, and sedating antihistamines), or other excluded medication.
Current psychiatric diagnosis based on the Mini-International Neuropsychiatric Interview (MINI) and/or the adult attention-deficit/hyperactivity disorder (ADHD) diagnostic interview.
Current substance abuse or substance dependence at any time.
The presence of a known neurological disorder or any major medical illness or injury impacting neurological/psychiatric function (e.g., diabetes, epilepsy, cerebral palsy, traumatic brain injury, significant environmental/toxic injury, neurodegenerative disorder, past meningitis/encephalitis).
General medical conditions: any major medical conditions that would interfere with involvement in the study or may affect central nervous system (CNS) function as judged by the investigative team.
History of clinically-significant head trauma.
Pregnancy
Any other condition that, in the opinion of the investigator, is a contraindication to participation
The presence of any ferrous metal implant, including orthodontics (e.g., braces), which may interfere with the MEG data acquisition and/or be a MRI safety concern.
Inability to correct visual acuity to 20/20 with corrective lenses (we can correct from +5 to -6 diopters in .5 diopter steps, separately for each eye, with non-magnetic corrective lenses in the laboratory).

Study & Design

Study Type: INTERVENTIONAL

Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Anodal Brain Stimulation	transcranial direct-current stimulation (tDCS)	Participants will receive anodal stimulation using high-definition tDCS
Cathodal Brain Stimulation	transcranial direct-current stimulation (tDCS)	Participants will receive cathodal stimulation using high-definition tDCS
Sham Brain Stimulation (Placebo)	transcranial direct-current stimulation (tDCS)	Participants will receive sham stimulation (placebo) using high-definition tDCS

Primary Outcome Measures

Name	Time	Method
Behavioral Performance (Reaction Time) on Cognitive Tests of Perceptual Processing	During the 90 minutes following stimulation	Do participants perform better in terms of reaction time following tDCS on behavioral measures of perceptual processing.
Behavioral Performance (Accuracy) on Cognitive Tests of Perceptual Processing	During the 90 minutes following stimulation	Do participants perform better in terms of accuracy following tDCS on behavioral measures of perceptual processing.

Secondary Outcome Measures

Name	Time	Method
The Power of Spontaneous Alpha Activity as Quantified by MEG Imaging	During the 90 minutes following stimulation	Does spontaneous alpha (9-13 Hz) power, as measured by MEG, get stronger following tDCS. Spontaneous activity refers to the level of background neural activity and is typically divided into frequency bands (e.g., alpha, gamma) that reflect the number of cycles per second. The outcome measure unit is nano-amperes square (nA\^2) since source-resolved MEG measures reflect electric current strength and not voltage units as in electroencephalography (EEG). The square is necessary since we examined power, which is the square of amplitude in the frequency domain. The unit is also commonly expressed as nAm\^2 since the strength of the electric current is over a defined length.
The Power of Oscillatory Alpha Activity as Quantified by MEG Imaging	During the 90 minutes following stimulation	Does oscillatory alpha neural activity, as measured by MEG, get stronger following tDCS. Oscillatory activity refers band-limited increases or decreases in the power of neural activity, relative to baseline, in response to a stimulus.
The Power of Spontaneous Gamma Activity as Quantified by MEG Imaging	During the 90 minutes following stimulation	Does spontaneous gamma (45-80 Hz) power, as measured by MEG, get stronger following tDCS. Spontaneous activity refers to the level of background neural activity and is typically divided into frequency bands (e.g., alpha, gamma) that reflect the number of cycles per second. The outcome measure unit is nano-amperes square (nA\^2) since source-resolved MEG measures reflect electric current strength and not voltage units as in electroencephalography (EEG). The square is necessary since we examined power, which is the square of amplitude in the frequency domain. The unit is also commonly expressed as nAm\^2 since the strength of the electric current is over a defined length.
The Power of Oscillatory Gamma Activity as Quantified by MEG Imaging	During the 90 minutes following stimulation	Does oscillatory gamma neural activity, as measured by MEG, get stronger following tDCS. Oscillatory activity refers band-limited increases or decreases in the power of neural activity, relative to baseline, in response to a stimulus.