Researchers from the University of Nottingham believe they may have uncovered a novel, targeted treatment for Tourette syndrome.
The findings, published in Trends in Cognitive Sciences, indicate that increases in the neurochemical gamma aminobutyric acid (GABA) during adolescence contribute to an improvement in the physical and vocal tics associated with the disorder.
“This is potentially a very important finding,” said researcher Stephen Jackson, PhD. “A widely held view has been that unwanted movements such as tics in Tourette syndrome are actively suppressed through the recruitment of frontal brain areas involved in volitional action and cognitive control. The finding that individuals with Tourette syndrome exhibit increased GABA in brain areas linked to the planning and selection of movements offers a more parsimonious account for how tics might be controlled in Tourette syndrome.”
Previously, the decrease in tics seen throughout adolescence and into adulthood was attributed to learned suppression, however researchers now believe that the primary inhibitory transmitter GABA, which controls the excitability of neurons, plays a central role.
“Motor excitability is reduced locally within brain motor areas through the operation of GABA-mediated ‘tonic inhibition’,” said Jackson. In previous studies, MRI of people with Tourette syndrome showed a reduction of GABA levels up to 50%. During adolescence, changes in the brain contribute to increased levels of GABA, which the researchers believe helps to curb the prevalence of tics as patients get older.
In the future, the researchers believe that a treatment that mimics the way in which GABA blocks nerve transmission in areas of the brain responsible for motor function could help Tourette patients who struggle to control their tics.
“This finding needs to be further replicated but if it proves to be a robust finding it may have important implications for therapies for neurodevelopmental disorders,” Jackson said.