Exploring Neuromodulation Effects of Low Intensity Non-Thermal Transcranial Focused Ultrasound on Motor Circuits in Animals and Humans

  • Huang, Ying-Zu (PI)
  • Chen, Rou Shayn (CoPI)
  • Hsieh, Tsung-Hsun (CoPI)
  • Liu, Hao-Li (CoPI)
  • Weng, Yi-Hsin (CoPI)

Project: National Science and Technology CouncilNational Science and Technology Council Academic Grants

Project Details


Non-invasive transcranial brain stimulation, e.g. repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), is capable of inducing after-effects outlasting the stimulation period through plasticity-like mechanisms and has been approved for therapeutic purposes in several countries. All these techniques have major limits: the stimulation is relatively superficial and cannot go deeper than the cortical layer of the brain, and their effects are variable. Hence, there is an unmet need for a novel transcranial brain stimulation technique for modulating a deeper area and for more consistent effects. In contrast to high intensity focused ultrasound that has shown its success in tissue ablation through a thermo effect, ultrasound at a much lower intensity that does not damage the tissue has shown the ability to generate reversible changes in the neuronal circuits since the beginning of 20 century. Recently, few studies have shown transient effects of low intensity non-thermal transcranial focused ultrasound (tFUS) on human brain circuits. Hence, tFUS seems to be an ideal candidate for developing the novel non-invasive brain stimulation technique. In pilot experiments (in a previous MOST project), we found that tFUS was able to induce changes in the motor excitability outlasting stimulation for several minutes without evidence of tissue damage in histology in rats. To extend from the pilot study, the current project is designed to, firstly, optimize tFUS protocols in animals based on our preliminary results. Secondly, a device mounting a thin tFUS transducer module to the surface of a TMS figure-of-eight coil will be built for human studies. Thirdly, we will test the effect of a short train of tFUS on human motor excitability and inhibition with TMS parameter, i.e. motor evoked potential (MEP), short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF). Fourthly, we will look for protocols to induce longer-lasting modulation after-effects of tFUS on motor cortical circuits in humans. Last, the behavior effect of the later tFUS protocols will be tested. Through this project, we will understand the neuromodulation effects of low intensity non-thermal transcranial focused ultrasound on motor circuits in more details, and develop protocols for humans. The knowledge from this project will be helpful for developing modulation technique of tFUS for other, e.g. deeper, brain circuits. Furthermore, the technique could be applied for exploring neurophysiology and pathophysiology of diseases, and even for therapeutic purposes in the future.

Project IDs

Project ID:PC10901-1991
External Project ID:MOST108-2314-B182-015-MY3
Effective start/end date01/08/2031/07/21


  • focused
  • ultrasound
  • transcranial magnetic stimulation
  • motor evoked potential (MEP)
  • short-interval intracortical inhibition (SICI)
  • intracortical facilitation (ICF)


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