Interhemispheric Interaction of Parieto-Motor Cortico-Cortical Plasticity



Status:Recruiting
Conditions:Healthy Studies
Therapuetic Areas:Other
Healthy:No
Age Range:18 - 55
Updated:11/14/2018
Start Date:November 15, 2018
End Date:August 31, 2019
Contact:Elaine P Considine, R.N.
Email:considinee@ninds.nih.gov
Phone:(301) 435-8518

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Interhemispheric Interaction of Parieto-Motor Cortico-Cortical Plasticity in Human Brain

Background:

The two hemispheres of the brain are connected. Changes in one hemisphere affect the other
through this connection. Research has shown that training new skills in one hand improves the
same skills for the other hand. Researchers want to learn more about how the brain works to
transfer the skills to the other hand.

Objective:

To learn how changes on one side of the brain affect the other side. To study the activity of
the left and right sides of the brain in healthy adults.

Eligibility:

Healthy volunteers ages 18-55 years old who are right-handed.

Design:

Participants will be screened with a medical history and physical exam. They will complete a
questionnaire about their handedness. This may be done on paper or on a computer.
Participants may have urine pregnancy tests.

Participants will have 2 study visits.

Participants will have a structural magnetic resonance imaging (MRI) scan. MRI uses a strong
magnetic field and radio waves to take pictures of the brain. The scanner is a metal cylinder
in a strong magnetic field. Participants will lie on a table that slides in and out of the
cylinder.

Participants will have transcranial magnetic stimulation (TMS). Two wire coils will be placed
on the scalp. A brief electrical current passes through the coil and creates a magnetic pulse
that affects brain activity. Participants may be asked to tense certain muscles or do simple
tasks during TMS.

Participants will have electromyography. Small sticky pad electrodes will be attached to the
skin on the hands. Muscle activity will be recorded during the TMS procedure.

Objective:

The purpose of this study is to evaluate the effect of long-term potentiation (LTP)-like
cortical plasticity induced by parieto-motor cortico-cortical paired associative stimulation
(cc-PAS) on the contralateral hemisphere and interhemispheric interactions in normal brain
using dual-site transcranial magnetic stimulation (TMS). We will explore the ipsilateral and
contralateral effects of cc-PAS over the left primary motor cortex (M1). We hypothesize that
the motor evoked potential (MEP) at S50 (the motor evoked potential) will change after cc-PAS
in the left hemisphere, which stimulates M1 after PPC (effective cc-PAS), not only on the
right first dorsal interosseous (FDI) muscle, but also the left FDI muscle.

In addition, we hypothesize that the MEP at S50 will change after cc-PAS in the left
hemisphere, which stimulates PPC after M1 (ineffective cc-PAS), on the right FDI muscle but
not the left FDI muscle.

Study population

We intend to study 15 healthy-volunteers to have 12 who complete the study. Subjects will
complete up to one screening visit and two study visits involving two intervention.

Design

Subjects will come for one screening visit and two outpatient study visits. The screening
visit and the first study visit can be performed the same day. The second study visit will be
done approximately 1 week after the first one. TMS-induced electromyographic (EMG) activity
of hand muscles will be recorded as MEPs. Using single TMS measure on both the left and right
M1, we will measure MEPs and input-out (I-O) curve for the right and left FDI muscle and
abductor digiti minimi (ADM) muscle, respectively. Using a paired-pulse TMS paradigm,
interhemispheric inhibition (IHI) from the left M1 to the right M1, short-interval
intracortical inhibition (SICI) and intracortical facilitation (ICF) will be measured on the
left FDI and ADM muscles. Then, the subjects will undergo two plasticity induction procedures
of the parieto-motor cc-PAS sessions. One of those is the hypothesized efficacious cc-PAS
session and the other one is the control, a hypothesized ineffective cc-PAS session. The two
sessions will be separated by approximately one week. Each session consists of 100 pairs of
double stimulation to the left PPC and left M1. MEPs, I-O curve on the bilateral M1, IHI from
the left M1 to the right M1, SICI and ICF will be remeasured during the 60 min after
receiving cc-PAS.

Outcome measures

Primary outcome:

The primary outcome measure will be MEP amplitude from the bilateral M1 with respect to time
(before, immediately and 30-45 min after intervention) after induction of cc-PAS plasticity
over the left hemisphere in each session. The amplitude of MEPs on each side of M1 will be
compared between before and after cc-PAS with respect to time, using ANOVA in each session.

Secondary outcome:

The degree of IHI from the left M1 to the right M1, SICI and ICF with respect to time
(before, immediately and 30-45 min after intervention) will be compared by the ANOVA test.
The degree of IHI and the change of IHI will be correlated with the primary outcome as
measured with a correlation analysis.

- INCLUSION CRITERIA:

- Between the age of 18 and 55 years

- Right-handed

- English speaking

- Ability to give informed consent

EXCLUSION CRITERIA:

- Illegal drugs use within the past 6 months based on history alone

- Abnormal findings on neurologic examination

- Have more than 7 alcoholic drinks a week in the case of a woman or 14 alcoholic drinks
a week in the case of a man

- History of or current brain tumor, stroke, head trauma with loss of consciousness >few
seconds, epilepsy or seizures

- History of or current episode of major depression or any major psychiatric illness
(axis I disorders)

- Current diagnosis of neurologic disorder

- Presence of pacemaker, intracardiac lines, implanted pumps or stimulators, or metal
objects inside the eye or skull. Dental fillings and dental braces are allowed.

- Open scalp wounds or scalp infection

- Employees and/or staff of HMCS/NINDS

- Taking benzodiazepines at the time of the entire study or within 12 days prior to the
study. NOTE: Medication will not be stopped or held for participation in this study.

- Taking, at the time of the entire study or within 2 weeks prior to the study, any
medication that acts as a central nervous system stimulant or that is known to lower
seizure threshold, including, imipramine, amitriptyline, doxepin, nortriptyline,
maprotiline, chlorpromazine, foscarnet, ganciclovir, ritonavir, amphetamines,
ketamine, gamma-hydroxybutyrate (GHB), theophylline, mianserin, fluoxetine,
fluvoxamine, paroxetine, sertraline, citalopram, reboxetine, venlafaxine, duloxetine,
bupropion, mirtazapine, fluphenazine, pimozide, haloperidol, olanzapine, quetiapine,
aripiprazole, ziprasidone, risperidone, chloroquine, mefloquine, imipenem, penicillin,
ampicillin, cephalosporins, metronidazole, isoniazid, levofloxacin, cyclosporine,
chlorambucil, vincristine, methotrexate, cytosine arabinoside, BCNU, lithium,
antihistamines, and sympathomimetics. NOTE: Medication will not be stopped or help for
participation in this study.

- Being pregnant

- You may not be eligible to have MRI or TMS in this study if:

- You have metal in your body which would make having an MRI scan unsafe, such as
pacemakers, stimulators, pumps, aneurysm clips, metallic prostheses, artificial
heart valves, cochlear implants or shrapnel fragments, or if you were a welder or
metal worker, since you may have small metal fragments in the eye.

- You are uncomfortable in small closed spaces (you have claustrophobia) so that
you would feel uncomfortable in the MRI machine.

- You are not able to lie comfortably on your back for up to 1 hour

- You have a hearing loss reported in the history or detected in the routine
physical examination
We found this trial at
1
site
9000 Rockville Pike
Bethesda, Maryland 20892
301-496-2563
Phone: 800-411-1222
National Institutes of Health Clinical Center The National Institutes of Health (NIH) Clinical Center in...
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Bethesda, MD
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