Training-Induced Plasticity in Human Motor and Sensory Systems

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DESCRIPTION (provided by applicant): Research on plasticity in motor systems has for the most part developed separately from work on sensory plasticity, as if training-induced changes to the brain affected each of these systems in isolation. The planned studies explore the idea that influences of learning are more extensive, and in the sensorimotor system, spread from motor to somatosensory areas of the brain and vice versa. The proposed studies will systematically explore two hypotheses about neuroplasticity: (1) that motor learning changes perceptual function and the function of somatosensory areas of the brain, and (2) that somatosensory training changes both motor function and motor areas of the brain. Our plan is to address the effects of motor learning on sensory systems and of somatosensory perceptual training on motor systems by using a cohesive approach that is similar for both hypotheses and combines psychophysical, neurophysiological and neuroimaging techniques. With respect to the first hypothesis, we will conduct behavioral tests of the idea that motor learning and perceptual change have a similar time course and that after motor learning, movements follow altered perceptual boundaries. We will use fMRI resting-state functional connectivity analyses to test the idea that motor learning is associated with changes to sensory areas of the brain and these changes are linked to behavioral measures of learning and perceptual change. We will test for cortical changes in sensory function by using electroencephalography (EEG) to record somatosensory evoked-potentials (SEPs) and relate changes in SEPs to measures of motor learning. For the second hypothesis, we will conduct behavioral tests of the idea that somatosensory perceptual training improves the rate of motor learning and produces persistent changes in movement that can be measured for periods of up to one week. We will use resting state imaging to test the idea that somatosensory training strengthens functional connectivity bilaterally in motor areas of the brain. We will use trans-cranial magnetic stimulation (TMS) to test for changes associated with somatosensory training in the excitability of primary motor cortex. The ability to quantify changes to brain plasticity that accompany both somatosensory training and motor learning may permit a better understanding of the broader effects of neurological rehabilitation on sensorimotor disorders. Imaging the sensory and motor networks of the brain that are associated with both somatosensory and motor learning may also lead to better diagnoses and tracking of brain neuroplasticity during therapy.