Learning and switching between stimulus-saccade associations in Parkinson's disease.

Making flexible associations between what we see and what we do is important for many everyday tasks. Previous work in patients with focal lesions has shown that the control of saccadic eye movements in such contexts relies on a network of areas in the frontal cerebral cortex. These regions are reci...

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Main Authors: Hodgson, T, Sumner, P, Molyva, D, Sheridan, R, Kennard, C
Format: Journal article
Language:English
Published: 2013
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author Hodgson, T
Sumner, P
Molyva, D
Sheridan, R
Kennard, C
author_facet Hodgson, T
Sumner, P
Molyva, D
Sheridan, R
Kennard, C
author_sort Hodgson, T
collection OXFORD
description Making flexible associations between what we see and what we do is important for many everyday tasks. Previous work in patients with focal lesions has shown that the control of saccadic eye movements in such contexts relies on a network of areas in the frontal cerebral cortex. These regions are reciprocally connected with structures in the basal ganglia although the contribution of these sub-cortical structures to oculomotor control in complex tasks is not well understood. We report the performance of patients with idiopathic Parkinsons disease (PDs) in a test which required learning and switching between arbitrary cue-saccade rules. In Experiment 1 feedback was given following each response which reliably indicated which of the two possible rules was correct. PDs were slower to learn the first cue-saccade association presented, but did not show increased error or reaction time switch costs when switching between two rules within blocks. In a follow up experiment the feedback given by the computer was adjusted to be probabilistic such that executing a response based upon the "correct" rule only resulted in positive feedback on 80% of trials. Under these conditions patients were impaired in terms of response latencies and number of errors. In all conditions PDs showed multi-stepping/hypometria of saccades consistent with a motoric deficit in executing actions based on cognitive cues. The findings are consistent with a role for the nigrostriatal dopamine system in the reinforcement of saccade-response-outcome associations. Intact performance of PDs when associations are not stochastically reinforced suggests that striatal learning systems are complemented by cognitive representations of task rules which are unaffected in the early stages of PD.
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spelling oxford-uuid:d11510cc-b09f-4b87-ac0b-1e943fcaa35f2022-03-27T07:54:26ZLearning and switching between stimulus-saccade associations in Parkinson's disease.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:d11510cc-b09f-4b87-ac0b-1e943fcaa35fEnglishSymplectic Elements at Oxford2013Hodgson, TSumner, PMolyva, DSheridan, RKennard, CMaking flexible associations between what we see and what we do is important for many everyday tasks. Previous work in patients with focal lesions has shown that the control of saccadic eye movements in such contexts relies on a network of areas in the frontal cerebral cortex. These regions are reciprocally connected with structures in the basal ganglia although the contribution of these sub-cortical structures to oculomotor control in complex tasks is not well understood. We report the performance of patients with idiopathic Parkinsons disease (PDs) in a test which required learning and switching between arbitrary cue-saccade rules. In Experiment 1 feedback was given following each response which reliably indicated which of the two possible rules was correct. PDs were slower to learn the first cue-saccade association presented, but did not show increased error or reaction time switch costs when switching between two rules within blocks. In a follow up experiment the feedback given by the computer was adjusted to be probabilistic such that executing a response based upon the "correct" rule only resulted in positive feedback on 80% of trials. Under these conditions patients were impaired in terms of response latencies and number of errors. In all conditions PDs showed multi-stepping/hypometria of saccades consistent with a motoric deficit in executing actions based on cognitive cues. The findings are consistent with a role for the nigrostriatal dopamine system in the reinforcement of saccade-response-outcome associations. Intact performance of PDs when associations are not stochastically reinforced suggests that striatal learning systems are complemented by cognitive representations of task rules which are unaffected in the early stages of PD.
spellingShingle Hodgson, T
Sumner, P
Molyva, D
Sheridan, R
Kennard, C
Learning and switching between stimulus-saccade associations in Parkinson's disease.
title Learning and switching between stimulus-saccade associations in Parkinson's disease.
title_full Learning and switching between stimulus-saccade associations in Parkinson's disease.
title_fullStr Learning and switching between stimulus-saccade associations in Parkinson's disease.
title_full_unstemmed Learning and switching between stimulus-saccade associations in Parkinson's disease.
title_short Learning and switching between stimulus-saccade associations in Parkinson's disease.
title_sort learning and switching between stimulus saccade associations in parkinson s disease
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