Motor Activity, Motor Neuroplasticity
Conditions
Keywords
transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), electroencephalography (EEG)
Brief summary
Investigating modulation of motor cortex excitability by transcranial magnetic stimulation and transcranial direct current stimulation.
Detailed description
Purpose of this pilot study is to modulate the motor cortex excitability by transcranial magnetic stimulation and transcranial direct current stimulation. Electromyography will be recorded on right abductor digiti minimi muscle to find the motor threshold and measure motor evoked potentials for each healthy participant. In addition, electroencephalography (EEG) data will be collected on the scalp with a high-density EEG net. Eighteen healthy participants will be in this study. Each participant will be seated in a reclining chair and applied non-invasive magnetic and electrical stimulations on the scalp. At baseline, the participant's resting motor threshold (RMT) will be estimated by adjusting the intensity of TMS applied on the left motor cortex to achieve motor-evoked potentials of about 50 uV with 10 TMS pulses at a rate of 0.25 Hz. Then a 3-condition, 3-session, 6-sequence randomized crossover experiment will be used to characterize and compare three versions of tDCS stimulation: anode, cathode, sham. Before and after a 10-min tDCS condition is applied, TMS pulses at 120% of RMT intensity will be applied for 10 minutes and TMS-evoked potential and motor-evoked potential amplitudes will be measured. Each session has at least 1-day gap to remove outlasting effects. We will also be collecting structural magnetic resonance imaging (sMRI) to target primary motor cortex precisely.
Interventions
DEVICEanodal tDCS
The participant will receive anodal tDCS with 2 mA for 10 minutes on the left motor cortex.
DEVICEcathodal tDCS
The participant will receive cathodal tDCS with -2 mA for 10 minutes on the left motor cortex.
DEVICEsham tDCS
The participant will receive sham tDCS with 2 mA for 40 seconds on the left motor cortex which mimics the skin sensations as active tDCS interventions.
Sponsors
National Institute of Mental Health (NIMH)
University of North Carolina, Chapel Hill
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Masking description
This is a double-blind and cross-over study.
Intervention model description
Each participant will be assigned to 2 active and sham conditions on a different day.
Eligibility
Sex/Gender
MALE
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* Male * Between the ages of 18 and 35 * Right-handed * Capacity to understand all relevant risks and potential benefits of the study (informed consent) * Willing to comply with all study procedures and be available for the duration of the study * Speak and understand English
Exclusion criteria
* Prior concussion * Diagnosis of eating disorder (current or within the past 6 months) * Diagnosis of obsessive compulsive disorder (lifetime) * 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, HIV/AIDS, malignancy, liver or renal impairment) * Prior brain surgery * Any brain devices/implants, including cochlear implants and aneurysm clips * Traumatic brain injury * 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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Changes in Motor-evoked Potentials Ratios | right before and after 2mA tDCS stimulation for 10 minutes at each session | The investigators will record motor-evoked potentials and calculate changes in between before and after 2mA tDCS stimulation for 10 minutes. |
| Changes in TMS-evoked Potentials Ratios | right before and after 2mA tDCS stimulation for 10 minutes at each session | The investigators will record TMS-evoked potentials using EEG and calculate changes in between before and after 2mA tDCS stimulation for 10 minutes. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Changes in Resting-state EEG Dynamics Ratios | 4 minutes recordings before and after each 2mA tDCS stimulation for 10 minutes at each session | The investigators will record participants' resting state for 4 minutes using EEG (2 minutes for eyes-closed and 2 minutes for eyes-open) |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Anode -> Cathode -> Sham During 3 study visits, participants will receive anodal tDCS first, then cathodal tDCS, then sham tDCS. For all three tDCS conditions, two electrodes will be applied to the scalp (one on the left motor cortex, one on the right supraorbital cortex) for 10 minutes. | 4 |
| Anode -> Sham -> Cathode During 3 study visits, participants will receive anodal tDCS first, then sham tDCS, then cathodal tDCS. For all three tDCS conditions, two electrodes will be applied to the scalp (one on the left motor cortex, one on the right supraorbital cortex) for 10 minutes. | 3 |
| Cathode -> Anode -> Sham During 3 study visits, participants will receive cathodal tDCS first, then anodal tDCS, then sham tDCS. For all three tDCS conditions, two electrodes will be applied to the scalp (one on the left motor cortex, one on the right supraorbital cortex) for 10 minutes. | 3 |
| Cathode -> Sham -> Anode During 3 study visits, participants will receive cathodal tDCS first, then sham tDCS, then anodal tDCS. For all three tDCS conditions, two electrodes will be applied to the scalp (one on the left motor cortex, one on the right supraorbital cortex) for 10 minutes. | 3 |
| Sham -> Anode -> Cathode During 3 study visits, participants will receive sham tDCS first, then anodal tDCS, then cathodal tDCS. For all three tDCS conditions, two electrodes will be applied to the scalp (one on the left motor cortex, one on the right supraorbital cortex) for 10 minutes. | 3 |
| Sham -> Cathode -> Anode During 3 study visits, participants will receive sham tDCS first, then cathodal tDCS, then anodal tDCS. For all three tDCS conditions, two electrodes will be applied to the scalp (one on the left motor cortex, one on the right supraorbital cortex) for 10 minutes. | 3 |
| Total | 19 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 | FG002 | FG003 | FG004 | FG005 |
|---|---|---|---|---|---|---|---|
| Washout (at Least 3 Days) | Withdrawal by Subject | 1 | 0 | 0 | 0 | 0 | 0 |
Baseline characteristics
| Characteristic | Anode -> Sham -> Cathode | Cathode -> Anode -> Sham | Cathode -> Sham -> Anode | Sham -> Anode -> Cathode | Sham -> Cathode -> Anode | Anode -> Cathode -> Sham | Total |
|---|---|---|---|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical Between 18 and 65 years | 3 Participants | 3 Participants | 3 Participants | 3 Participants | 3 Participants | 4 Participants | 19 Participants |
| Age, Continuous | 25.33 years STANDARD_DEVIATION 6.94 | 22.33 years STANDARD_DEVIATION 1.24 | 20.66 years STANDARD_DEVIATION 0.47 | 22 years STANDARD_DEVIATION 4.24 | 25.33 years STANDARD_DEVIATION 6.12 | 28.75 years STANDARD_DEVIATION 6.68 | 24.31 years STANDARD_DEVIATION 5.84 |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 1 Participants | 0 Participants | 1 Participants | 2 Participants | 0 Participants | 4 Participants |
| Race (NIH/OMB) Black or African American | 0 Participants | 0 Participants | 2 Participants | 1 Participants | 0 Participants | 1 Participants | 4 Participants |
| Race (NIH/OMB) More than one race | 1 Participants | 1 Participants | 0 Participants | 0 Participants | 0 Participants | 1 Participants | 3 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 2 Participants | 1 Participants | 1 Participants | 1 Participants | 1 Participants | 2 Participants | 8 Participants |
| Region of Enrollment United States | 3 Participants | 3 Participants | 3 Participants | 3 Participants | 3 Participants | 4 Participants | 19 Participants |
| Sex: Female, Male Female | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Sex: Female, Male Male | 3 Participants | 3 Participants | 3 Participants | 3 Participants | 3 Participants | 4 Participants | 19 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk |
|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 19 | 0 / 18 | 0 / 18 |
| other Total, other adverse events | 0 / 19 | 0 / 18 | 0 / 18 |
| serious Total, serious adverse events | 0 / 19 | 0 / 18 | 0 / 18 |
Outcome results
Primary
Changes in Motor-evoked Potentials Ratios
The investigators will record motor-evoked potentials and calculate changes in between before and after 2mA tDCS stimulation for 10 minutes.
Time frame: right before and after 2mA tDCS stimulation for 10 minutes at each session
Population: One participant signed the consent form but data for this participant was not recorded.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Anodal tDCS | Changes in Motor-evoked Potentials Ratios | 1.32 Ratio (unit: uV) | Standard Error 0.09 |
| Cathodal tDCS | Changes in Motor-evoked Potentials Ratios | 0.73 Ratio (unit: uV) | Standard Error 0.07 |
| Sham tDCS | Changes in Motor-evoked Potentials Ratios | 1.03 Ratio (unit: uV) | Standard Error 0.05 |
Primary
Changes in TMS-evoked Potentials Ratios
The investigators will record TMS-evoked potentials using EEG and calculate changes in between before and after 2mA tDCS stimulation for 10 minutes.
Time frame: right before and after 2mA tDCS stimulation for 10 minutes at each session
Population: One participant signed the consent form but data for this participant was not recorded.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Anodal tDCS | Changes in TMS-evoked Potentials Ratios | 1.5 Ratio (unit: uV) | Standard Deviation 0.5 |
| Cathodal tDCS | Changes in TMS-evoked Potentials Ratios | 0.8 Ratio (unit: uV) | Standard Deviation 0.4 |
| Sham tDCS | Changes in TMS-evoked Potentials Ratios | 1.1 Ratio (unit: uV) | Standard Deviation 0.4 |
Secondary
Changes in Resting-state EEG Dynamics Ratios
The investigators will record participants' resting state for 4 minutes using EEG (2 minutes for eyes-closed and 2 minutes for eyes-open)
Time frame: 4 minutes recordings before and after each 2mA tDCS stimulation for 10 minutes at each session
Population: One participant signed the consent form but data for this participant was not recorded.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Anodal tDCS | Changes in Resting-state EEG Dynamics Ratios | 1.2 Ratio (unit: uV) | Standard Deviation 0.7 |
| Cathodal tDCS | Changes in Resting-state EEG Dynamics Ratios | 0.8 Ratio (unit: uV) | Standard Deviation 0.3 |
| Sham tDCS | Changes in Resting-state EEG Dynamics Ratios | 1.1 Ratio (unit: uV) | Standard Deviation 0.5 |