Modulation of Spontaneous Cortical Activity by tDCS: BRAIN Initiative I

The Impact of Spontaneous Cortical Activity on Neural Oscillations and Behavioral Performance: Evidence From High-definition tDCS and MEG

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT03672747

Enrollment

133

Registered

2018-09-14

Start date

2019-02-20

Completion date

2023-05-31

Last updated

2024-07-31

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Brain Function

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.

Interventions

DEVICEtranscranial direct-current stimulation (tDCS)

20 minutes duration using high-definition system with center-surround configuration

Study design

Allocation

RANDOMIZED

Intervention model

CROSSOVER

Primary purpose

BASIC_SCIENCE

Masking

DOUBLE (Subject, Investigator)

Masking description

Double-blinded

Intervention model description

Full crossover; all participants complete all conditions

Eligibility

Sex/Gender

ALL

Age

19 Years to 72 Years

Healthy volunteers

Yes

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).

Design outcomes

Primary

Measure	Time frame	Description
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.
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.

Secondary

Measure	Time frame	Description
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.

Countries

United States

Participant flow

Pre-assignment details

Note that 133 participants were enrolled using a cross-over design and randomized into one of six tracks. There was at least a 7 day washout between each of the three visits and this was the same across the six tracks.

Participants by arm

Arm	Count
All Study Participants All participants received all interventions.	124
Total	124

Withdrawals & dropouts

Period	Reason	FG000	FG001	FG002	FG003	FG004	FG005
Overall Study	Lost to Follow-up	1	1	2	2	2	1

Baseline characteristics

Characteristic	All Study Participants
Age, Categorical <=18 years	0 Participants
Age, Categorical >=65 years	21 Participants
Age, Categorical Between 18 and 65 years	103 Participants
Age, Continuous	44 years
Ethnicity (NIH/OMB) Hispanic or Latino	14 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	110 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants
Mental health questionnaire	124 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants
Race (NIH/OMB) Asian	12 Participants
Race (NIH/OMB) Black or African American	8 Participants
Race (NIH/OMB) More than one race	3 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants
Race (NIH/OMB) White	101 Participants
Region of Enrollment United States	124 participants
Sex: Female, Male Female	65 Participants
Sex: Female, Male Male	59 Participants

Adverse events

Event type	EG000 affected / at risk	EG001 affected / at risk	EG002 affected / at risk
deaths Total, all-cause mortality	0 / 133	0 / 133	0 / 133
other Total, other adverse events	0 / 133	0 / 133	0 / 133
serious Total, serious adverse events	0 / 133	0 / 133	0 / 133

Outcome results

Primary

Behavioral Performance (Accuracy) on Cognitive Tests of Perceptual Processing

Do participants perform better in terms of accuracy following tDCS on behavioral measures of perceptual processing.

Time frame: During the 90 minutes following stimulation