Tics are rapid, involuntary movements or sound matters. Often the vowels and motor constraints also occur together, then one speaks of Tourette syndrome. Some of those affected suffer greatly from the uncontrollable twitches and calls, since other people sometimes react with incomprehension and rejection. Researchers from Charité Berlin have now found out which brain network is responsible for the development of tics.
For the study, Andreas Horn's research group took advantage of a rare form of the disorder. The team conducted a literature review and identified 22 patients in whom the disease had been shown to have been caused by injury, such as traumatic brain injury or stroke. Using extensive mapping of the lesions, Horn and his colleagues found that most of the affected regions were part of a common network.
An extensive network of tics
The coherent areas are distributed almost over the whole brain: from the island bark over the cinguli gyrus, which is located above the bar to the thalamus and the cerebellum. Even if the individual areas were repeatedly associated with the development of tics, according to Horn, it has so far remained unclear which of the regions the tics triggered and which are only active in order to compensate for incorrect processes.
To substantiate their findings, the experts went one step further. Neurosurgeons sometimes implant brain pacemakers in particularly severe Tourette's syndrome when medication or behavioral therapy does not help. In 30 such patients, the research group used brain scans to take a close look at the areas where the stimulation electrodes were placed. "Those with severe tic disorder benefited the most when deep brain stimulation directly targeted the regions of the tic network," says Christos Ganos, first author of the study. The researchers hope that their findings will help improve the treatment of the condition.
