Pharmacological Mechanisms of Low-intensity Focused Ultrasound for Motor Cortex Neuroplasticity (NCT04923659)
🩺 Plain-English Summary (8th-Grade Level)
Low-intensity focused ultrasound (LIFUS) has been shown to be an effective and safe non-invasive brain stimulation technique, capable of reaching greater brain depth and a greater spatial resolution than other brain stimulation tools. Its use as a potential clinical tool for treatment of neurological disorders is reliant on an understanding of its mechanisms of action. Although it has been shown to induce immediate (online) and prolonged (offline) changes in plasticity in the motor cortex, researchers have not studied its effects on neurotransmitter receptors and ion channels responsible for neuronal signaling in humans. The purpose of this study is to explore the effects of online and offline LIFUS stimulation in tandem with administration of various brain-active drugs, to elucidate the effects of this technique on specific cortical receptors and channels. 20 healthy, screened subjects will be recruited to participate in 5 sessions in-lab. Each session will represent the double-blinded administration of four known and studied pharmacological agents known to safely induce changes in the motor cortex, as well as a placebo. Investigators will use carbamazepine (sodium channel blocker), lorazepam (GABAA positive allosteric modulator), nimodipine (calcium channel blocker), and dextromethorphan (glutamate N-Methyl-D-aspartate receptor antagonist). Single- and paired-pulse transcranial magnetic stimulation (TMS) measures will be recorded for online LIFUS before and after drug intervention, and induction of offline LIFUS during placebo will be compared with its induction following the various drug interventions. Investigators predict that due to the differential effects of online and offline LIFUS on motor parameters, the mechanisms in which it alters the receptors and channels of interest will also be differentially modulated.
Who can join: To join this study, participants generally need to meet the listed inclusion criteria (1 items) and avoid the listed exclusions (24 items).
Location: Toronto Western Hospital — Toronto, Ontario
📋 "Do I Qualify?" — 1-Minute Self Screener
Instant ChecklistCheck every box below. If you can check all of them, you may meet the study's basic screening requirements (final eligibility is confirmed by the site team).
Usually NOT eligible if any of the following apply:
- Exclusion Criteria:
- Diagnosed with any gait or postural disorders
- Major neurological disease or disorder
- Major musculoskeletal or nerve disorder, or disorder of hands, wrists and upper limbs
- History of stroke or seizure
- Diagnosed with dementia
- Diagnosed with myasthenia gravis or acute narrow angle glaucoma
- Has intracranial implant(s) or device(s)
- Has an implanted cardiac pacemaker or implantable cardioverter-defibrillator (ICD)
- Presence of metal implanted in body that is contraindicated in TMS
- Caffeine or chocolate consumption 1-2 hours before study sessions
- Consumption of grapefruit juice 24 hours before study sessions
🔍 Extracted verbatim from the official NIH eligibility criteria. Always confirm with the study coordinator.
📍 All Participating Trial Locations (1 Sites)
- Toronto Western Hospital — Toronto, Ontario
💰 Cost, Insurance & Patient Rights
- 100% Free Items: The investigational treatment and protocol-required procedures are supplied at zero cost by the sponsor.
- Routine Patient Care: Under federal law (ACA § 2709) and many state statutes, routine care costs are covered during participation.
- Voluntary Participation: You may withdraw at any time without affecting your standard medical care.