Implicit sequence learning in people with Parkinson’s disease

Implicit sequence learning involves learning about dependencies in sequences of events without intent to learn or awareness of what has been learned. Sequence learning is related to striatal dopamine levels, striatal activation, and integrity of white matter connections. People with Parkinson’s dise...

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Main Authors: Katherine R Gamble, Thomas J. Cummings, Steven E Lo, Pritha T Ghosh, James H Howard, Darlene V. Howard
Format: Article
Language:English
Published: Frontiers Media S.A. 2014-08-01
Series:Frontiers in Human Neuroscience
Subjects:
Online Access:http://journal.frontiersin.org/Journal/10.3389/fnhum.2014.00563/full
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author Katherine R Gamble
Thomas J. Cummings
Steven E Lo
Pritha T Ghosh
James H Howard
James H Howard
James H Howard
Darlene V. Howard
author_facet Katherine R Gamble
Thomas J. Cummings
Steven E Lo
Pritha T Ghosh
James H Howard
James H Howard
James H Howard
Darlene V. Howard
author_sort Katherine R Gamble
collection DOAJ
description Implicit sequence learning involves learning about dependencies in sequences of events without intent to learn or awareness of what has been learned. Sequence learning is related to striatal dopamine levels, striatal activation, and integrity of white matter connections. People with Parkinson’s disease (PD) have degeneration of dopamine-producing neurons, leading to dopamine deficiency and therefore striatal deficits, and they have difficulties with sequencing, including complex language comprehension and postural stability. Most research on implicit sequence learning in PD has used motor-based tasks. However, because PD presents with motor deficits, it is difficult to assess whether learning itself is impaired in these tasks. The present study used an implicit sequence learning task with a reduced motor component, the Triplets Learning Task (TLT). People with PD and age- and education-matched healthy older adults completed three sessions (each consisting of 10 blocks of 50 trials) of the TLT. Results revealed that the PD group was able to learn the sequence, however, when learning was examined using a Half Blocks analysis (Nemeth et al., 2013), which compared learning in the 1st 25/50 trials of all blocks to that in the 2nd 25/50 trials, the PD group showed significantly less learning than Controls in the 2nd Half Blocks, but not in the 1st. Nemeth et al. hypothesized that the 1st Half Blocks involve recall and reactivation of the sequence learned, thus reflecting hippocampal-dependent learning, while the 2nd Half Blocks involve proceduralized behavior of learned sequences, reflecting striatal-based learning. The present results suggest that the PD group had intact hippocampal-dependent implicit sequence learning, but impaired striatal-dependent learning. Thus, sequencing deficits in PD are likely due to striatal impairments, but other brain systems, such as the hippocampus, may be able to partially compensate for striatal decline to improve performance.
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spelling doaj.art-307371ece757474d8af111ff3ac204872022-12-22T01:06:47ZengFrontiers Media S.A.Frontiers in Human Neuroscience1662-51612014-08-01810.3389/fnhum.2014.0056391319Implicit sequence learning in people with Parkinson’s diseaseKatherine R Gamble0Thomas J. Cummings1Steven E Lo2Pritha T Ghosh3James H Howard4James H Howard5James H Howard6Darlene V. Howard7Georgetown UniversityMedStar Georgetown University HospitalMedStar Georgetown University HospitalGeorge Washington UniversityThe Catholic University of AmericaGeorgetown UniversityGeorgetown UniversityGeorgetown UniversityImplicit sequence learning involves learning about dependencies in sequences of events without intent to learn or awareness of what has been learned. Sequence learning is related to striatal dopamine levels, striatal activation, and integrity of white matter connections. People with Parkinson’s disease (PD) have degeneration of dopamine-producing neurons, leading to dopamine deficiency and therefore striatal deficits, and they have difficulties with sequencing, including complex language comprehension and postural stability. Most research on implicit sequence learning in PD has used motor-based tasks. However, because PD presents with motor deficits, it is difficult to assess whether learning itself is impaired in these tasks. The present study used an implicit sequence learning task with a reduced motor component, the Triplets Learning Task (TLT). People with PD and age- and education-matched healthy older adults completed three sessions (each consisting of 10 blocks of 50 trials) of the TLT. Results revealed that the PD group was able to learn the sequence, however, when learning was examined using a Half Blocks analysis (Nemeth et al., 2013), which compared learning in the 1st 25/50 trials of all blocks to that in the 2nd 25/50 trials, the PD group showed significantly less learning than Controls in the 2nd Half Blocks, but not in the 1st. Nemeth et al. hypothesized that the 1st Half Blocks involve recall and reactivation of the sequence learned, thus reflecting hippocampal-dependent learning, while the 2nd Half Blocks involve proceduralized behavior of learned sequences, reflecting striatal-based learning. The present results suggest that the PD group had intact hippocampal-dependent implicit sequence learning, but impaired striatal-dependent learning. Thus, sequencing deficits in PD are likely due to striatal impairments, but other brain systems, such as the hippocampus, may be able to partially compensate for striatal decline to improve performance.http://journal.frontiersin.org/Journal/10.3389/fnhum.2014.00563/fullAgingsequence learningimplicit learningParkinson’s diseaseimplicit sequence learning
spellingShingle Katherine R Gamble
Thomas J. Cummings
Steven E Lo
Pritha T Ghosh
James H Howard
James H Howard
James H Howard
Darlene V. Howard
Implicit sequence learning in people with Parkinson’s disease
Frontiers in Human Neuroscience
Aging
sequence learning
implicit learning
Parkinson’s disease
implicit sequence learning
title Implicit sequence learning in people with Parkinson’s disease
title_full Implicit sequence learning in people with Parkinson’s disease
title_fullStr Implicit sequence learning in people with Parkinson’s disease
title_full_unstemmed Implicit sequence learning in people with Parkinson’s disease
title_short Implicit sequence learning in people with Parkinson’s disease
title_sort implicit sequence learning in people with parkinson s disease
topic Aging
sequence learning
implicit learning
Parkinson’s disease
implicit sequence learning
url http://journal.frontiersin.org/Journal/10.3389/fnhum.2014.00563/full
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AT jameshhoward implicitsequencelearninginpeoplewithparkinsonsdisease
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