Abstract
Suppression of unwanted motor responses forms the basis of goal-directed behaviour and can be disrupted by Parkinson’s disease. People with Parkinson’s (PwP) can show maladaptive reward-driven behaviours in the form of impulse control behaviours, which are associated with use of the dopaminergic treatments used to alleviate the motor symptoms of the disease. However, the effects of Parkinson’s itself on impulsive behaviour and control are unclear – empirical studies have yielded mixed findings, and some imaging studies have shown a functional deficit in the absence of a measurable change in behaviour. Here, we investigated the effects of Parkinson’s on response activation and control by studying the dynamics of response in standard inhibitory control tasks – the Stop Signal and Simon tasks – using a continuous measure of response force. Our results show that response inhibition appears to be intact in PwP, even when using a more sensitive measure of behavioural control relative to traditional button-press measures. Our findings provide some clarity as to the effects of Parkinson’s on response inhibition and show continuous response force measurement can provide a sensitive means of detecting erroneous response activity in PwP, which could also be generalised to studying related processes in other populations.
Open data Data and analysis can be found on the Open Science Framework (osf.io/kx6h3/)
Pre-print template Wiernik, B.M. (2019, October 11). Preprint templates. osf.io/hsv6a/
Footnotes
We would like to thank Dr Matthew Sullivan for his input in making sure the study design was suitable for people with Parkinson’s. This research was funded by an Economic and Social Research Council PhD studentship for JSP, and an Economic and Social Research Council grant to EP [ES/K013564/1].
3 The MDS-UPDRS was used to identify tremor dominant and postural instability and gait dominant patients using the same method reported by Stebbins et al. (2013).
4 As in McBride et al. (2018) we used a constant in addition to a standard deviation threshold in order to reject noise and more reliably detect responses.
