Cognitive sequence learning in Parkinson's disease and amnestic mild cognitive impairment: Dissociation between sequential and non-sequential learning ... [An article from: Neuropsychologia]
Book Details
PublisherElsevier
ISBN / ASINB000PDSS0G
ISBN-13978B000PDSS02
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Description
This digital document is a journal article from Neuropsychologia, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.
Description:
Evidence suggests that dopaminergic mechanisms in the basal ganglia (BG) are important in the learning of sequential associations. To test the specificity of this hypothesis, we assessed never-medicated patients with Parkinson's disease (PD) and amnestic mild cognitive impairment (aMCI) using a chaining task. In the training phase of the chaining task, each link in a sequence of stimuli leading to reward is trained step-by-step using feedback after each decision, until the complete sequence is learned. In the probe phase of the chaining task, the context of stimulus-response associations must be used (the position of the associations in the sequence). Results revealed that patients with PD showed impaired learning during the training phase of the chaining task, but their performance was spared in the probe phase. In contrast, patients with aMCI with prominent medial temporal lobe (MTL) dysfunctions showed intact learning during the training phase of the chaining task, but their performance was impaired in the probe phase of the chaining task. These results indicate that when dopaminergic mechanisms in the BG are dysfunctional, series of stimulus-response associations are less efficiently acquired, but their sequential manner is maintained. In contrast, MTL dysfunctions may result in a non-sequential learning of associations, which may indicate a loss of contextual information.
Description:
Evidence suggests that dopaminergic mechanisms in the basal ganglia (BG) are important in the learning of sequential associations. To test the specificity of this hypothesis, we assessed never-medicated patients with Parkinson's disease (PD) and amnestic mild cognitive impairment (aMCI) using a chaining task. In the training phase of the chaining task, each link in a sequence of stimuli leading to reward is trained step-by-step using feedback after each decision, until the complete sequence is learned. In the probe phase of the chaining task, the context of stimulus-response associations must be used (the position of the associations in the sequence). Results revealed that patients with PD showed impaired learning during the training phase of the chaining task, but their performance was spared in the probe phase. In contrast, patients with aMCI with prominent medial temporal lobe (MTL) dysfunctions showed intact learning during the training phase of the chaining task, but their performance was impaired in the probe phase of the chaining task. These results indicate that when dopaminergic mechanisms in the BG are dysfunctional, series of stimulus-response associations are less efficiently acquired, but their sequential manner is maintained. In contrast, MTL dysfunctions may result in a non-sequential learning of associations, which may indicate a loss of contextual information.
