Authors: Peter Brown
Researchers at Washington University School of Medicine (St. Louis, MO, USA) have utilized structural MRI to identify areas in the brains of children with Tourette’s syndrome that appear markedly different when compared with the same areas in children without the neuropsychiatric disorder, potentially revealing new target regions and avenues of study in Tourette’s syndrome.
The results of the study, recently published in Molecular Psychiatry, demonstrates evidence for abnormal brain structure in children and youth with Tourette’s syndrome, consistent with previous findings.
“In this study, we found changes primarily in brain regions connected to sensation and sensory processing,” commented co-principal investigator Kevin Black (Washington University).
“Just as you or I might cough or sneeze due to a cold, a person with Tourette’s frequently will have a feeling that something is wrong, and the tic makes it feel better,” Black elaborated. “A young man who frequently clears his throat may report that doing so is a reaction to a tickle or some other unusual sensation in his throat. Or a young woman will move her shoulder when it feels strange, and the movement, which is a tic, will make the shoulder feel better.”
In the largest study of its kind, the team conducted MRI scans at four sites in America to study the brains of 103 children with Tourette’s and compared them with scans of another 103 participants of the same age and sex but without the disorder. The scans of individuals with Tourette’s displayed significantly more gray matter in the thalamus, the hypothalamus and the midbrain than in those without the disorder.
Additionally, the researchers observed less white matter around the orbital prefrontal cortex and in the medial prefrontal cortex when compared to children without the condition. Less white matter could suggest less efficient transmission of sensations, whereas extra gray matter may indicate that nerve cells are sending extra signals.
Further research is still required to determine whether the extra gray matter is transmitting information that may contribute to tics or whether reduced amounts of white matter elsewhere in the brain may influence the movements and vocalizations that characterize the disorder. However identifying these changes in the brain could provide scientists with new targets to better understand and treat Tourette’s.
“This doesn’t tell us what happened to make the brain look this way,” Black explained. “Are there missing cells in certain places, or are the cells just smaller? And are these regions changing as the brain tries to resist tics? Or are the differences we observed contributing to problems with tics? We simply don’t know the answers yet.”
The team will continue their research and aims to replicate these findings in additional patients to determine if and how the brain regions identified may contribute to Tourette’s syndrome and therefore utilize these results to potentially develop more effective therapies.
SOURCES: Greene DJ, Williams AC, Koller JM, Schlaggar BL, Black KJ, The Tourette Association of America Neuroimaging Consortium. Brain structure in pediatric Tourette syndrome. Mol. Psychiatry. doi: 10.1038/mp.2016.194 (2016) (Epub ahead of print);