Distinctive tics suppression network in Gilles de la Tourette syndrome distinguished from suppression of natural urges using multimodal imaging

Abstract

Background and objectivesGilles de la Tourette syndrome (GTS) is a neuropsychiatric disorder characterized by tics. A hallmark of GTS is the ability to voluntarily suppress tics. Our aim was to distinguish the neural circuits involved in the voluntary suppression of ocular tics in GTS patients from blink suppression in healthy subjects.MethodsFifteen GTS patients and 22 healthy control subjects were included in a multimodal study using eye-tracker recordings during functional MRI (fMRI). The ability to suppress tics/blinks was compared both on subjective (self-rating) and objective (eye-tracker) performance. For fMRI analysis we used a novel designed performance-adapted block design analysis of tic/blink suppression and release based on eye-tracker monitoring.ResultsWe found that the subjective self-reported ability to suppress tics or blinks showed no significant correlation with objective task performance. In GTS during successful suppression of tics, the dorsal anterior cingulate cortex and associated limbic areas showed increased activation. During successful suppression of eye blinks in healthy subjects, the right ventrolateral prefrontal cortex and supplementary and cingulate motor areas showed increased activation.ConclusionsThese findings demonstrate that GTS patients use a characteristic limbic suppression strategy. In contrast, control subjects use the voluntary sensorimotor circuits and the classical ‘stop’ network to suppress natural urges. The employment of different neural suppression networks provides support for cognitive behavioral therapy in GTS.

Non-invasive Brain Stimulation for the Treatment of Gilles de la Tourette Syndrome

“…Additionally, IFG activity during tic inhibition was positively correlated with the ability to inhibit tics ( 83 ). Furthermore, fMRI studies suggest an increased activity in the caudate nucleus together with a decreased activity of the thalamus, putamen and globus pallidus ( 109 ), an increased activity of the left anterior cingulate cortex ( 131 ) and increased activity in the dorsal anterior cingulate cortex and associated limbic areas ( 132 ) during tic inhibition. Given not only an increased activity during voluntary tic suppression ( 83 ), but also a positive correlation of this activity with the ability of tic suppression ( 83 ), it seems reasonable to boost IFG activity by means of rTMS.…”

Pathophysiologie des Gilles-de-la-Tourette-Syndroms

“…Die mit Tic-Unterdrückung assoziierte neuronale Aktivität bei Tourette-Patienten unterscheidet sich von der bei der Unterdrückung automatischer Bewegungen (z. B. Blinzeln) bei gesunden Kontrollen auftretenden Aktivierung [67]. Willentliche Tic-Kontrolle folgt einem somatotopen Muster, wobei sie in Körperregionen, die am wenigsten von Tics betroffen sind, am effektivsten ist [68].…”

“…eine Aktivitätszunahme im linken anterioren Zingulums [71] assoziiert. In einer jüngeren Arbeit fand sich während Tics-Unterdrückung eine erhöhte Aktivität bilateral im mittleren Temporalkortex, bilateral im frontalen Augenfeld, im linken Gyrus occipitalis inferior, im rechten anterioren präfrontalen Kortex sowie im rechten inferioren parietalen Kortex [67].…”

Amplified engagement of prefrontal cortex during control of voluntary action in Tourette syndrome

“…fMRI studies characterising neural processes in Tourette syndrome are rarely free of interpretive confounds. Overt tic suppression studies cannot meaningfully compare patients' brain activity during suppression periods to controls who do not tic (van der Salm et al, 2018).…”

“…In addition, accidental expression of tics during instructed suppression periods may confound the interpretation of tic suppression versus 'free ticcing' studies, while results in task-based studies may be affected by covert tic suppression. Instead, 'intentional inhibition' tasks enable direct comparison of Tourette syndrome and control participants, revealing for example heightened dorsal anterior cingulate and striatal activity in Tourette syndrome when participants are instructed to inhibit eye blinks (and suppress ocular tics) (Mazzone et al, 2010;van der Salm et al, 2018).…”