Computational model of the role of sensory disorganization in focal task-specific dystonia

We present a new computational model for the development of task-specific f ocal dystonia. The purpose of the model is to explain how altered sensory r epresentations can lead to abnormal motor behavior. Dystonia is described a s the result of excessive gain through a sensorimotor loop. The gain is det ermined in part by the sensory cortical area devoted to each motor function , and behaviors that lead to abnormal increases in sensory cortical area ar e predicted to lead to dystonia. Properties of dystonia including muscular co-contraction, overflow movements, and task specificity are predicted by p roperties of a linear approximation to the loop transformation. We provide simulations of several different mechanisms that can cause the gain to exce ed 1 and the motor activity to become sustained and uncontrolled. The model predicts that normal plasticity mechanisms may contribute to worsening of symptoms over time.