Impact of Spaced iTBS on Plasticity in the Motor Cortex

Summary

The goal of this clinical trial is to explore the effects of non-invasive brain stimulation protocols using intermittent theta-burst stimulation (iTBS) on brain plasticity in healthy, right-handed individuals aged 18 to 50 years. Brain plasticity is the brain's ability to change through growth or reorganization. iTBS is a form of transcranial magnetic stimulation (TMS), where magnetic pulses are applied to the scalp using a coil. These pulses pass through the scalp, and can alter brain activity in the area underneath the coil. Based on previous research conducted in animals and humans, researchers believe that iTBS can strengthen the connections between cells in the brain, leading to improved brain plasticity.

This trial will compare the effects of the compressed iTBS (iTBS-c) protocol, which is commonly used to treat depression, and the spaced iTBS (iTBS-s) protocol. Researchers want to find out which protocol is better able to produce changes in brain plasticity. Sham iTBS (iTBS-sh) will be used as a control to make the results of the study more reliable.

Participants will complete 5 study visits within the span of 3 months, including:

* Screening assessments to determine eligibility (Visit 1);
* Calibration iTBS session (Visit 2) to assess tolerability of brain stimulation;
* Three experimental iTBS sessions (iTBS-s, iTBS-c, and iTBS-sh) in a randomized order (Visits 3-5), each separated by at least 72 hours. During each session, the study team will stimulate the motor cortex and record the muscle activity of your hand to measure changes in brain plasticity.

Conditions

• Healthy Control Subjects

Interventions

DEVICE

Compressed iTBS

Intermittent Theta-Burst Stimulation (iTBS) is a form of non-invasive brain stimulation that uses magnetic pulses applied to the scalp using a coil. iTBS will be used to stimulate the left motor cortex to enhance long-term potentiation (LTP)-like activity, a physiological mechanism associated with brain plasticity. During the intervention, the study team will conduct two pre-iTBS TMS measurements (Pre-30 and Pre-15). Participants will then complete iTBS-c (active comparator), which will be delivered unilaterally to the left motor cortex. Following iTBS-c, five post-iTBS TMS measurements (Post-0, 15, 30, 45, and 60) will be obtained. Motor evoked potentials (MEPs) will be recorded from the right APB, ADM, and FDI muscles to assess the effects of the stimulation. The MCF-B65, MCF-P-B65, and/or Cool-B65 A/P TMS coils will be used, alongside the MagPro R30 or the MagPro X100 TMS stimulators to deliver the intervention.

DEVICE

Spaced iTBS

Intermittent Theta-Burst Stimulation (iTBS) is a form of non-invasive brain stimulation that uses magnetic pulses applied to the scalp using a coil. iTBS will be used to stimulate the left motor cortex to enhance long-term potentiation (LTP)-like activity, a physiological mechanism associated with brain plasticity. During the intervention, the study team will conduct two pre-iTBS TMS measurements (Pre-30 and Pre-15). Participants will then complete iTBS-s (experimental study intervention), which will be delivered unilaterally to the left motor cortex. Following iTBS-s, five post-iTBS TMS measurements (Post-0, 15, 30, 45, and 60) will be obtained. Motor evoked potentials (MEPs) will be recorded from the right APB, ADM, and FDI muscles to assess the effects of the stimulation. The MCF-B65, MCF-P-B65, and/or Cool-B65 A/P TMS coils will be used, alongside the MagPro R30 or the MagPro X100 TMS stimulators to deliver the intervention.

DEVICE

Sham iTBS

Intermittent Theta-Burst Stimulation (iTBS) is a form of non-invasive brain stimulation that uses magnetic pulses applied to the scalp using a coil. iTBS will be used to stimulate the left motor cortex to enhance long-term potentiation (LTP)-like activity, a physiological mechanism associated with brain plasticity. During the intervention, the study team will conduct two pre-iTBS TMS measurements (Pre-30 and Pre-15). Participants will then complete iTBS-sh (sham comparator), which will be delivered unilaterally to the left motor cortex. Following iTBS-sh, five post-iTBS TMS measurements (Post-0, 15, 30, 45, and 60) will be obtained. Motor evoked potentials (MEPs) will be recorded from the right APB, ADM, and FDI muscles to assess the effects of the stimulation. The MCF-B65, MCF-P-B65, and/or Cool-B65 A/P TMS coils will be used, alongside the MagPro R30 or the MagPro X100 TMS stimulators to deliver the intervention.

Sponsors & Collaborators

• Centre for Addiction and Mental Health

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

SINGLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

50 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2024-11-13

Primary Completion

2026-02-01

Completion

2026-02-01

Countries

• Canada

Study Locations