Compromised reactive but intact proactive inhibitory motor control in Tourette disorder

Indrajeet Indrajeet,Cyril Atkinson-Clement,Yulia Worbe,Supriya Ray,Pierre Pouget

doi:10.1038/s41598-022-05692-z

Abstract

Tourette disorder (TD) is characterized by tics, which are sudden repetitive involuntary movements or vocalizations. Deficits in inhibitory control in TD patients remain inconclusive from the traditional method of estimating the ability to stop an impending action, which requires careful interpretation of a metric derived from race model. One possible explanation for these inconsistencies is that race model’s assumptions of independent and stochastic rise of GO and STOP process to a fixed threshold are often violated, making the classical metric to assess inhibitory control less robust. Here, we used a pair of metrics derived from a recent alternative model to address why stopping performance in TD is unaffected despite atypical neural circuitry. These new metrics distinguish between proactive and reactive inhibitory control and estimate them separately. When these metrics in adult TD group were contrasted with healthy controls (HC), we identified robust deficits in reactive control, but not in proactive control in TD. The TD group exhibited difficulty in slowing down the speed of movement preparation, which they rectified by their intact ability to postpone the movement.

Highlights

Tourette disorder (TD) is characterized by tics, which are sudden repetitive involuntary movements or vocalizations
A total of 63 TD and 34 healthy control (HC) performed an Emotional Stop Signal Task (ESST), which required them to refrain from pressing a key in response to an infrequent stop-signal[21]
Like earlier studies we observed that neither stopping behavior nor the metric derived from race model was able to distinguish between TD and HC

Summary

Introduction

Tourette disorder (TD) is characterized by tics, which are sudden repetitive involuntary movements or vocalizations. Tourette disorder (TD) represents a relevant model of inhibition impairment due to its major clinical sign: tics They corresponded to sudden, repetitive, non-rhythmic, involuntary or semi-voluntary movements and/ or vocalization[22,23] and are frequently considered as “fragments of motor behavior that escape voluntary motor control”, related to a deficiency in inhibitory control of a ctions[20,24,25]. A recent s tudy[30] examined volitional (proactive and reactive) and automatic inhibition in primary tic disorder using conditional stop-signal and masked priming task respectively. They found that proactive control was intact and automatic inhibition was impaired. If trials with short intervals between the go and stop signal are removed from SSRT estimation, the difference reported in published studies between HC and disorder groups mostly d isappears[33–35]

Methods

Results

Conclusion