Systematic examination of low-intensity ultrasound parameters on human motor cortex excitability and behaviour
- University of Toronto, Canada
- National Taiwan University, Taiwan
- Toronto Western Hospital, Canada
- Sunnybrook Research Institute, Canada
Abstract
Low-intensity transcranial ultrasound (TUS) can non-invasively modulate human neural activity. We investigated how different fundamental sonication parameters influence the effects of TUS on the motor cortex (M1) of 16 healthy subjects by probing cortico-cortical excitability and behaviour. A low-intensity 500 kHz TUS transducer was coupled to a transcranial magnetic stimulation (TMS) coil. TMS was delivered 10 ms before the end of TUS to the left M1 hotspot of the first dorsal interosseous muscle. Varying acoustic parameters (pulse repetition frequency, duty cycle and sonication duration) on motor-evoked potential amplitude were examined. Paired-pulse measures of cortical inhibition and facilitation, and performance on a visuomotor task was also assessed. TUS safely suppressed TMS-elicited motor cortical activity, with longer sonication durations and shorter duty cycles when delivered in a blocked paradigm. TUS increased GABAA-mediated short-interval intracortical inhibition and decreased reaction time on visuomotor task but not when controlled with TUS at near-somatosensory threshold intensity.
Data availability
Data used for this study are included in the manuscript and supporting files.Files for 3D printing the stimulating devices and custom MATLAB scripts used for stimulation have been deposited into a cited GitHub repository.
Article and author information
Author details
Funding
Canadian Institutes of Health Research (Banting and Best Doctoral Award)
- Anton Fomenko
Canadian Institutes of Health Research (Foundation Grant,FDN 154292)
- Robert Chen
University of Manitoba (Clinician Investigator Program)
- Anton Fomenko
Canada Research Chairs (Neuroscience)
- Andres M Lozano
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Human subjects: All patients gave written informed consent and the protocol was approved by the UHN Research Ethics Board (Protocol #18-5082) in accordance with the Declaration of Helsinki on the use of human subjects in experiments.
Copyright
© 2020, Fomenko et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Systematic examination of low-intensity ultrasound parameters on human motor cortex excitability and behaviour
eLife 9:e54497.
https://doi.org/10.7554/eLife.54497
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