Tourette syndrome (TS) is a neurological disorder characterised by the occurrence of vocal and motor tics1. The pathophysiology of TS has been linked to a substantial reduction in the number of inhibitory GABAergic interneurons found within the striatum2, leading to increased neural ‘noise’ within the cortical-striatal-thalamic-cortical [CSTC] circuit implicated in movement production3. In the current study, we used electroencephalography (EEG) to investigate increased neural noise in a group of 19 adults with TS compared to a matched neurotypical control group. We operationalised neural noise in this study as increased trial-by-trial variability in the magnitude and/or the timing of responses to a discrete somatosensory stimulation event. Specifically, we examined trial-by-trial variability in responses to a single pulse of median nerve electrical stimulation [MNS]. Our results demonstrate that the P100 somatosensory evoked potential (SEP), which has been associated with conscious perception of tactile stimuli11, was significantly increased in the TS group. Importantly, however, while the timing, temporal variability, and spatial topography of early- and mid-latency SEP components (e.g., N20, P45, N60, P100) did not differ in the TS group, when compared to matched controls, trial-by-trial variability was substantially increased in the TS group, but this was normalised in response to stimulation. These findings may indicate that the trial-by-trial recruitment of neuronal sensorimotor populations is less stable at rest in individuals with TS compared to controls but may normalise in response to stimulation.

The authors have declared no competing interest.

This study was funded by the Medical Research Council, Parkinsons UK, and EPSRC.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

School of Psychology Ethics committee of University of Nottingham gave ethical approval for this work

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All data produced in the present study are available upon reasonable request to the authors