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Impact of Spaced ITBS on Plasticity in the Motor Cortex

Healthy Control Subjects

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 0);
* Calibration iTBS session (Visit 1) to assess tolerability of brain stimulation;
* Three experimental iTBS sessions (iTBS-s, iTBS-c, and iTBS-sh) in a randomized order (Visits 2-4), 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 thumb to measure changes in brain plasticity.

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Participation Requirements

  • Sex:

    ALL

  • Eligible Ages:

    18 to 50

Participation Criteria

Inclusion Criteria:

1. Age 18 years or above, and less than 51 years.
2. Right handedness, assessed using the Edinburgh Handedness Inventory (EHI).
3. Sufficiently proficient in English to complete the required study assessments, as per investigator judgement.
4. Willingness and capacity to provide informed consent.
5. Willingness to comply with all study procedures.

Exclusion Criteria:

1. Age 17 years or less, or greater than 51 years, as brain plasticity is known to be affected by age.
2. Current use of any psychotropic medications (e.g. anti-depressants, anti-convulsants, anti-psychotics, etc.).
3. Contraindications to transcranial magnetic stimulation (TMS), as per investigator judgment.
4. Lifetime history of any Diagnostic and Statistical Manual of Mental Disorders (DSM-5) diagnosis, assessed using the Structured Clinical Interview for DSM-5 (SCID-5), except simple phobias.
5. Left handed or ambidextrous, assessed using the EHI, to minimize the heterogeneity in cortical excitability and plasticity.
6. Self-reported history of seizures and/or other major neurological conditions, as per investigator judgement, due to the risk of seizures associated with TMS in individuals with a heightened risk.

Study Location

Centre for Addiction and Mental Health
Centre for Addiction and Mental Health
Toronto, Ontario
Canada

Contact Study Team

Backup Contact

Tarek Rajji, MD

Backup Contact

Christoph Zrenner, MD

Primary Contact

Christoph Zrenner, MD

[email protected]
(416) 535-8501
Backup Contact

Daniel Blumberger, MD

Backup Contact

Dewi Clark, MHSc

[email protected]
(416) 535-8501
Backup Contact

Heather Brooks, PhD

Study Sponsored By
Centre for Addiction and Mental Health
Participants Required
More Information
Study ID: NCT06735794