Brain functional connectivity in Tourette syndrome
Tourette syndrome, a neurodevelopmental disorder, causes motor and phonic "tics" or uncontrollable repeated behaviors and vocalizations. People affected by Tourette syndrome can often suppress these tics for some time before the urges become overwhelming, and researchers have long wondered at the neural underpinnings of the suppression effort.

Now, in a new study using a non-invasive technique to measure brain activity called high-density electroencephalography (hdEEG), researchers have assessed the impact of tic suppression on functional connectivity between brain regions.

The team recorded the brain activity of 72 children, aged 8 to 16 years old, with Tourette syndrome using hdEEG, while they were ticcing freely and while they were suppressing their tics. The researchers then assessed connectivity between the different regions in the brain.

The authors found that connectivity between multiple brain regions was increased while children suppressed their tics. "Some of these regions are part of the default mode network, an array of brain regions engaged during internal thought processes such as daydreaming." Additionally, the researchers reported that functional brain connectivity during tic suppression was positively correlated with age, suggesting that the brain networks of tic suppression undergo developmental changes in response to the experience of tics.

The study highlights the brain mechanism involved in a temporary decrease in tic frequency, which could have therapeutic implications.

Biological Psychiatry: Cognitive Neuroscience and Neuroimaging