Physiology of Interregional Connectivity in the Human Brain

Summary

The purpose of this study is to understand the physiology of connectivity between cortical regions in the human brain in healthy participants and in patients with white matter lesions. Specifically, the investigators will examine the effects of paired associative stimulation (PAS) which consists in delivering brief (\< 1 ms) current pulses separated by a short millisecond-level time interval ("asynchrony") to two cortical areas. The used techniques are all non-invasive and considered safe in humans: transcranial magnetic stimulation (TMS), electroencephalography (EEG), magnetic resonance imaging (MRI), and functional MRI (fMRI). Based on prior literature in animals and human studies, it is hypothesized that PAS may increase or decrease effective connectivity between the stimulated areas depending on the asynchrony value. The main outcome measure is source-resolved EEG responses evoked by single-pulse TMS; this is a more direct measure of neuronal changes occurring at the targeted cortical area than motor evoked potentials (MEPs) or sensor-level EEG responses used in previous studies.

Conditions

• Healthy
• Stroke
• Traumatic Brain Injury
• Multiple Sclerosis

Interventions

DEVICE

Single-pulse transcranial magnetic stimulation (spTMS)

Single-pulse TMS (spTMS) will be delivered with a TMS stimulator (MagPro X100 w/ MagOption, MagVenture, Farum, Denmark) and a figure-of-eight TMS coil. 80 spTMS will be repeated at 0.2 Hz. An MRI-based TMS navigation system will be used to navigate the TMS coil (Localite, St Augustin, Germany).

DEVICE

Paired associative stimulation (PAS)

Paired associative stimulation (PAS) will be applied with two TMS stimulators (MagPro X100 w/ MagOption, MagVenture, Farum, Denmark) and two TMS coils. The pulses from each stimulator/coil will be repeated at 0.2 Hz, duration of run 15 minutes (180 pulses for each stimulator/coil). In different sessions, we will deliver PAS with different asynchrony values to examine their effects on effective connectivity. Coils will be navigated using an MRI-based TMS navigation system (Localite, St Augustin, Germany).

DEVICE

Repetitive transcranial magnetic stimulation (rTMS)

Repetitive TMS (rTMS) will be applied at 1 and 20 Hz with a TMS stimulator (MagPro X100 w/ MagOption, MagVenture, Farum, Denmark) and a figure-of-eight TMS coil. 300 rTMS pulses will be delivered during 1 and 20 Hz stimulation. An MRI-based TMS navigation system will be used to navigate the TMS coil (Localite, St Augustin, Germany).

Sponsors & Collaborators

• Northwestern University

  collaborator OTHER

• Shirley Ryan AbilityLab

  lead OTHER

Principal Investigators

• Tommi Raij, MD, PhD · Shirley Ryan AbilityLab 355 East Erie St, Chicago, IL Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL

Study Design

Allocation

NON_RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

85 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2017-05-31

Primary Completion

2020-11-30

Completion

2020-11-30

Countries

• United States

Study Locations