Dr. Legon earned a bachelor’s degree and a master’s degree in Kinesiology and Health Science at York University in Toronto and a doctoral degree in Kinesiology and Cognitive and Behavioral Neuroscience at the University of Waterloo in Ontario, Canada where he examined the use of transcranial magnetic stimulation (TMS) for the probing of somatosensory circuits to understand the role of sensory information for motor learning and control. He joined the Neurology Department at Sunnybrook hospital in Toronto as a post-doctoral fellow to apply these findings towards stroke recovery. He later joined Jamie Tyler’s lab at Virginia Tech as a post-doctoral fellow to study the use of transcranial focused ultrasound for human applications. Here, he successfully combined ultrasound stimulation with EEG and fMRI in humans and with Dr. Tyler were the first to demonstrate that low-intensity focused ultrasound (LIFU) can be safely used in humans to induce transient changes in cortical excitability that also affected behavior published in Nature Neuroscience in 2014. Since this seminal finding Dr. Legon spent time at the University of Minnesota in the Department of Physical Medicine and Rehabilitation and University of Virginia in the department of Neurosurgery where he demonstrated LIFU can be used to target the thalamus in humans and also developed the novel combination of TMS/LIFU to probe the effect of LIFU on human motor circuitry and behavior. LIFU is now a widely adopted and accepted new form of non-invasive neuromodulation due in part to Dr. Legon’s pioneering efforts.
The Legon lab primarily studies the use of low-intensity focused ultrasound (LIFU) for human neuromodulation applications and also has several collaborations using animal models. LIFU is an emerging form of noninvasive neuromodulation that uses mechanical energy to affect neuronal activity. The technology combines high spatial resolution with deep focal lengths providing unprecedented non-invasive access to the human brain. The enormous potential of LIFU stems from the ability to focus it through the intact skull to a millimeter-sized focal spot virtually anywhere in the brain. This makes it a powerful alternative to both invasive neurosurgical procedures and other non-invasive brain stimulation techniques. The lab is focused on understanding how LIFU affects human brain activity with the ultimate goal to translate these findings to clinical applications for addiction, pain and depression. The lab performs empirical acoustic testing as well as computer modelling of ultrasound wave propagation. Human subject studies employ several techniques including electroencephalography (EEG), electromyography (EMG), functional magnetic resonance imaging (fMRI), computed tomography (CT), transcranial magnetic stimulation (TMS), quantitative sensory testing (QST) and physiological monitoring (BP, HR, GSR and respiration rate).
Darmani, G., Bergmann, T.O., Pauly, K.B., Caskey, C.F., de Lecea, L., Fomenko, A., Fouragnan, E., Legon, W., Murphy, K.R., Nandi, T. and Phipps, M.A., 2021. Non-invasive transcranial ultrasound stimulation for neuromodulation. Clinical Neurophysiology.
Collins, M. N., Legon, W., & Mesce, K. A. (2021). The inhibitory thermal effects of focused ultrasound on an identified, single motoneuron. eneuro, 8(2).
Legon, W., Adams, S., Bansal, P., Patel, P. D., Hobbs, L., Ai, L., ... & Gillick, B. T. (2020). A retrospective qualitative report of symptoms and safety from transcranial focused ultrasound for neuromodulation in humans. Scientific reports, 10(1), 1-10.
Prada, F., Franzini, A., Moosa, S., Padilla, F., Moore, D., Solbiati, L., ... & Legon, W. (2020). In vitro and in vivo characterization of a cranial window prosthesis for diagnostic and therapeutic cerebral ultrasound. Journal of Neurosurgery, 134(2), 646-658.
Ai, L., Bansal, P., Mueller, J. K., & Legon, W. (2018). Effects of transcranial focused ultrasound on human primary motor cortex using 7T fMRI: a pilot study. BMC neuroscience, 19(1), 1-10.
Legon, W., Bansal, P., Tyshynsky, R., Ai, L., & Mueller, J. K. (2018). Transcranial focused ultrasound neuromodulation of the human primary motor cortex. Scientific reports, 8(1), 1-14.
Guo, H., Hamilton II, M., Offutt, S.J., Gloeckner, C.D., Li, T., Kim, Y., Legon, W., Alford, J.K. and Lim, H.H., 2018. Ultrasound produces extensive brain activation via a cochlear pathway. Neuron, 98(5), pp.1020-1030.
Legon, W., Ai, L., Bansal, P., & Mueller, J. K. (2018). Neuromodulation with single‐element transcranial focused ultrasound in human thalamus. Human brain mapping, 39(5), 1995-2006.
Mueller, J. K., Ai, L., Bansal, P., & Legon, W. (2017). Numerical evaluation of the skull for human neuromodulation with transcranial focused ultrasound. Journal of neural engineering, 14(6), 066012.
Legon, W., Punzell, S., Dowlati, E., Adams, S. E., Stiles, A. B., & Moran, R. J. (2016). Altered prefrontal excitation/inhibition balance and prefrontal output: markers of aging in human memory networks. Cerebral Cortex, 26(11), 4315-4326.
Ai, L., Mueller, J. K., Grant, A., Eryaman, Y., & Legon, W. (2016, August). Transcranial focused ultrasound for BOLD fMRI signal modulation in humans. In 2016 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) (pp. 1758-1761). IEEE.
Mueller, J. K., Ai, L., Bansal, P., & Legon, W. (2016). Computational exploration of wave propagation and heating from transcranial focused ultrasound for neuromodulation. Journal of neural engineering, 13(5), 056002.
Neren, D., Johnson, M. D., Legon, W., Bachour, S. P., Ling, G., & Divani, A. A. (2016). Vagus nerve stimulation and other neuromodulation methods for treatment of traumatic brain injury. Neurocritical care, 24(2), 308-319.
Opitz, A., Legon, W., Mueller, J., Barbour, A., Paulus, W., & Tyler, W. J. (2015). Is sham cTBS real cTBS? The effect on EEG dynamics. Frontiers in Human Neuroscience, 8, 1043.
Legon, W., Sato, T. F., Opitz, A., Mueller, J., Barbour, A., Williams, A., & Tyler, W. J. (2014). Transcranial focused ultrasound modulates the activity of primary somatosensory cortex in humans. Nature neuroscience, 17(2), 322-329.
Mueller, J., Legon, W., Opitz, A., Sato, T. F., & Tyler, W. J. (2014). Transcranial focused ultrasound modulates intrinsic and evoked EEG dynamics. Brain stimulation, 7(6), 900-908.
Opitz, A., Legon, W., Rowlands, A., Bickel, W. K., Paulus, W., & Tyler, W. J. (2013). Physiological observations validate finite element models for estimating subject-specific electric field distributions induced by transcranial magnetic stimulation of the human motor cortex. Neuroimage, 81, 253-264.
Legon, W., Rowlands, A., Opitz, A., Sato, T. F., & Tyler, W. J. (2012). Pulsed ultrasound differentially stimulates somatosensory circuits in humans as indicated by EEG and FMRI. PloS one, 7(12), e51177.