overview

I retired from active research on June 30, 2017. I continue to have an active ongoing relationship with the Department of Brain and Cognitive Sciences and the McGovern Institute for Brain Research at MIT, and undertake a variety of activities with collaborators.

Through the years, my research has focused primarily on two questions: 1) how does the brain handle the enormous complexity involved in making even the simplest movement. And, 2) how to utilize muscle synergies for establishing principled ways to restore limb kinematics compromised by stroke and/or brain injury.

With respect to the first theme, my collaborators and I provided evidence for a modular organization of the spinal cord in lower and higher vertebrates (rats, frogs and monkeys). A "module" is functional unit in the spinal cord that generates a specific motor output by expressing a specific pattern of muscle activation (muscle synergy). Such an organization might help to simplify the production of movements by reducing the degrees of freedom that need to be specified.

With respect to the second question, we have garnered experimental evidence that the muscle synergies with their coefficients of activation are affected by stroke and head injuries. On the strength of this observation, I continue to be interested in ongoing research and consult with various collaborators in quantitatively evaluating the relationship between affected muscle synergies and compromised limb kinematics. These studies provide a principled way to re-establish healthy movements.