Neuroplasticity and Imaging

  • Beth Fisher, PhD, PT --- Director

    The research at the NAIL aims to investigate brain-behavior relationships during motor skill learning and motor control in both non-disabled and brain-injured individuals using Transcranial magnetic stimulation. Transcranial magnetic stimulation (TMS) is a powerful, non-invasive tool for studying the human brain. Depending on stimulation parameters, TMS can excite or inhibit the brain allowing functional mapping of cortical regions (Hallett, 2000) thus providing information about the role of that brain area in specific behaviors. Post-intervention changes in cortico-motor excitability are providing insight into the effectiveness of rehabilitation strategies in stimulating neuroplasticity. The use of TMS will expand as it clearly supplements other tools that are used to examine human physiology, such as functional neuroimaging.

    The research program encompasses four major themes. The first theme aims to characterize and measure changes in cortical excitability in response to injury (stroke/ Parkinson's disease), training and rehabilitation. By applying single pulses, or paired pulses to the motor cortex, we can measure the excitability using motor evoked potentials recorded from the muscle. The second theme uses single pulse TMS and/or repetitive TMS to modulate the cortical function and study the effects of this modulation on motor behavior (control and learning). The key objective of these experiments is to reveal the specific role of brain areas in motor control and learning in non-disabled individuals and individuals with brain injury. The third theme entails exploring the possibility of using TMS as an adjunct therapeutic tool to enhance the effectiveness of training and rehabilitation. This is a relatively new and emerging research area that aims to investigate the efficacy of TMS to enhance experience-dependent neuroplasticity that implements recovery. The final theme investigates the role of cortical excitatory and inhibitory circuitries in motor control. Using ipsilateral silent period (iSP) as a measure of interhemispheric inhibition, this theme involves determining the relationship between iSP and motor skill level.