Practice-related changes in neural activation patterns investigated via wavelet-based clustering analysis

Authors

  • Jinae Lee,

    1. Department of Statistics, University of Georgia (UGA), Athens, Georgia
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  • Cheolwoo Park,

    1. Department of Statistics, University of Georgia (UGA), Athens, Georgia
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  • Kara A. Dyckman,

    1. Department of Psychology, University of Georgia (UGA), Athens, Georgia
    2. Department of Neuroscience, University of Georgia (UGA), Athens, Georgia
    3. The Bio-Imaging Research Center, University of Georgia (UGA), Athens, Georgia
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  • Nicole A. Lazar,

    1. Department of Statistics, University of Georgia (UGA), Athens, Georgia
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  • Benjamin P. Austin,

    1. UW Cardiovascular Research Center, University of Wisconsin School of Medicine and Public Health and the Department of Veterans Affairs (VA) Geriatric Research, Education and Clinical Center (GRECC), Madison, WI, USA
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  • Qingyang Li,

    1. Center for the Developing Brain, Child Mind Institute, New York, NY 10022, USA
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  • Jennifer E. McDowell

    Corresponding author
    1. Department of Psychology, University of Georgia (UGA), Athens, Georgia
    2. Department of Neuroscience, University of Georgia (UGA), Athens, Georgia
    3. The Bio-Imaging Research Center, University of Georgia (UGA), Athens, Georgia
    • Department of Statistics, University of Georgia (UGA), Athens, Georgia
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Correspondence to: Jennifer E. McDowell, Department of Psychology, UGA Psychology Building, Athens, GA 30602. E-mail: jemcd@uga.edu

Abstract

Objectives: To evaluate brain activation using functional magnetic resonance imaging (fMRI) and specifically, activation changes across time associated with practice-related cognitive control during eye movement tasks. Experimental design: Participants were engaged in antisaccade performance (generating a glance away from a cue) while fMR images were acquired during two separate test sessions: (1) at pre-test before any exposure to the task and (2) at post-test, after 1 week of daily practice on antisaccades, prosaccades (glancing toward a target), or fixation (maintaining gaze on a target). Principal observations: The three practice groups were compared across the two test sessions, and analyses were conducted via the application of a model-free clustering technique based on wavelet analysis. This series of procedures was developed to avoid analysis problems inherent in fMRI data and was composed of several steps: detrending, data aggregation, wavelet transform and thresholding, no trend test, principal component analysis (PCA), and K-means clustering. The main clustering algorithm was built in the wavelet domain to account for temporal correlation. We applied a no trend test based on wavelets to significantly reduce the high dimension of the data. We clustered the thresholded wavelet coefficients of the remaining voxels using PCA K-means clustering. Conclusion: Over the series of analyses, we found that the antisaccade practice group was the only group to show decreased activation from pre-test to post-test in saccadic circuitry, particularly evident in supplementary eye field, frontal eye fields, superior parietal lobe, and cuneus. Hum Brain Mapp 34:2276–2291, 2012. © 2012 Wiley Periodicals, Inc.

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