University of Southern California
Mrs T.H. Chan Division of Occupational Science and Occupational Therapy
Neural Plasticity and Neurorehabilitation Laboratory | Research

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Brain Stimulation

Brain Stimulation

Noninvasive brain stimulation is one way to modulate neural tissue in healthy individuals and after a stroke. Brain stimulation is thought to improve post-stroke motor recovery, as well as improve motor learning in healthy individuals. However, recent work has shown large inter-individual variability in how people respond to brain stimulation, with up to 50% of individuals showing little to no effects. Our work aims to use brain stimulation to probe mechanisms of learning and recovery after stroke, and to understand for whom noninvasive brain stimulation may work best.



Transcranial direct current stimulation (tDCS) is a promising way to modulate someone’s brain activity and make regions of the brain more or less excited. tDCS has shown promise in helping people recover motor function after stroke by increasing activity in the damaged brain. However, the stimulation seems to have effects not just in the part of the brain we’re stimulating, but across the whole brain, which produces a lot of variable results for patients. The goal of TICNET (tDCS-Induced Changes in the Motor Network) is to map out the effects of regional tDCS on the whole brain by measuring whole brain activity during tDCS (e.g., using fMRI with tDCS at the same time). The long-term goal of TICNET is to better understand brain network changes after local tDCS so we can make better and more specific tDCS treatments for patients after stroke.

Lefebvre, S., & Liew, S. L. (2017). Anatomical Parameters of tDCS to Modulate the Motor System after Stroke: A Review. Frontiers in Neurology, 8. Link to full text.

Dayan, E., López-Alonso, V., Liew, S.-L., & Cohen, L. G. (2018). Distributed cortical structural properties contribute to motor cortical excitability and inhibition. Brain Structure and Function. Advance online publication. Show abstract

Lopez-Alonso, V., Liew, S.-L., del Olmo, M. F., Cheeran, B., Sandrini, M., Abe, M., & Cohen, L. G. (2018). A preliminary comparison of motor learning across different non-invasive brain stimulation paradigms shows no consistent modulations. Frontiers in Neuroscience, 12, 253. Show abstract

Liew, S.-L., Thompson, T., Ramirez, J., Butcher, P., Taylor, J. A., & Celnik, P. A. (2018). Variable neural contributions to explicit and implicit learning during visuomotor adaptation. Frontiers in Neuroscience, 12, 610. Show abstract