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Learning from the past and expecting the future in Parkinsonism: Dopaminergic influence on predictions about the timing of future events.

Tomassini, A; Pollak, TA; Edwards, MJ; Bestmann, S (2019) Learning from the past and expecting the future in Parkinsonism: Dopaminergic influence on predictions about the timing of future events. Neuropsychologia, 127. pp. 9-18. ISSN 1873-3514 https://doi.org/10.1016/j.neuropsychologia.2019.02.003
SGUL Authors: Edwards, Mark John James

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Abstract

The prolonged reaction times seen in Parkinson's disease (PD) have been linked to a dopaminergic-dependent deficit in using prior information to prepare responses, but also have been explained by an altered temporal processing. However, an underlying cognitive mechanism linking dopamine, temporal processing and response preparation remains elusive. To address this, we studied PD patients, with or without medication, and age-matched healthy individuals using a variable foreperiod task requiring speeded responses to a visual stimulus occurring at variable onset-times, with block-wise changes in the temporal predictability of visual stimuli. Compared with controls, unmedicated patients showed impaired use of prior information to prepare their responses, as reflected by slower reaction times, regardless of the level of temporal predictability. Crucially, after dopamine administration normal performance was restored, with faster responses for high temporal predictability. Using Bayesian hierarchical drift-diffusion modelling, we estimated the parameters that determine temporal preparation. In this theoretical framework, impaired temporal preparation under dopaminergic depletion was driven by inflexibly high decision boundaries (i.e. participants were always extremely cautious). This indexes high levels of uncertainty about temporal predictions irrespectively of stimulus onset predictability. Our results suggest that dopaminergic depletion in PD affects the uncertainty of predictions about the timing of future events (temporal predictions), which are crucial for the anticipatory preparation of responses. Dopamine, which is affected in PD, controls the ability to predict the timing of future events.

Item Type: Article
Additional Information: © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/BY/4.0/).
Keywords: Dopamine, Drift-diffusion model, Motor preparation, Parkinson's Disease, Temporal expectation, Temporal processing, Uncertainty, 1109 Neurosciences, 1701 Psychology, 1702 Cognitive Science, Experimental Psychology
SGUL Research Institute / Research Centre: Academic Structure > Molecular and Clinical Sciences Research Institute (MCS)
Journal or Publication Title: Neuropsychologia
ISSN: 1873-3514
Language: eng
Dates:
DateEvent
April 2019Published
11 February 2019Published Online
6 February 2019Accepted
Publisher License: Creative Commons: Attribution 4.0
Projects:
Project IDFunderFunder ID
260424European Research Councilhttp://dx.doi.org/10.13039/501100000781
UNSPECIFIEDMedical Research Councilhttp://dx.doi.org/10.13039/501100000265
PubMed ID: 30763591
Go to PubMed abstract
URI: http://openaccess.sgul.ac.uk/id/eprint/110676
Publisher's version: https://doi.org/10.1016/j.neuropsychologia.2019.02.003

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