Surgical treatment for disabling Tourette's syndrome has been proven effective in cases presenting with self-injury. Deep Brain Stimulation surgery targeting the globus pallidus, thalamus and other areas of the brain may be effective in treating involuntary and possibly life-threatening tics. History In the 16th century, Andreas Vesalius and Francesco Piccolomini were the first to distinguish between white matter, the cortex, and the subcortical nuclei in the brain. About a century later, Thomas Willis noticed that the corpus striatum was typically discolored, shrunken, and abnormally softened in the cadavers of people who had died from paralysis. The view that the corpus striatum played such a large role in motor functions was the most prominent one until the 19th century when electrophysiologic stimulation studies began to be performed. For example, Gustav Fritsch and Eduard Hitzig performed them on dog cerebral cortices in 1870, while David Ferrier performed them, along with ablation studies, on cerebral cortices of dogs, rabbits, cats, and primates in 1876. During the same year, John Hughlings Jackson posited that the motor cortex was more relevant to motor function than the corpus striatum after carrying out clinical-pathologic experiments in humans. Soon it would be discovered that the theory about the corpus striatum would not be completely incorrect. By the late 19th century, a few hyperkinesias such as Huntington's chorea, post-hemiplegic choreoathetosis, Tourette's syndrome, and some forms of both tremor and dystonia were described in a clinical orientation. However, the common pathology was still a mystery. British neurologist William Richard Gowers called these disorders "general and functional diseases of the nervous system" in his 1888 publication entitled A Manual of Diseases of the Nervous System. It was not until the late 1980s and 1990s that sufficient animal models and human clinical trials were utilized to discover the specific involvement of the basal ganglia in the hyperkinesia pathology. In 1998, Wichmann and Delong made the conclusion that hyperkinesia is associated with decreased output from the basal ganglia, and in contrast, hypokinesia is associated with increased output from the basal ganglia. This generalization, however, still leaves a need for more complex models to distinguish the more nuanced pathologies of the numerous diverse hyperkinesias which are still being studied today. In the 2nd century, Galen was the first to define tremor as "involuntary alternating up-and-down motion of the limbs." Further classification of hyperkinetic movements came in the 17th and 18th centuries by Franciscus Sylvius