Practicerelated Changes in Neural Activation Patterns Investigated Via
r Human Brain Mapping 000:000–000 (2012) r Practice-Related Changes in Neural Activation Patterns Investigated via Wavelet-Based Clustering Analysis Jinae Lee,1 Cheolwoo Park,1 Kara A. Dyckman,2,3,4 Nicole A. Lazar,1 Benjamin P. Austin,5 Qingyang Li,6 and Jennifer E. McDowell2,3,4* 1Department of Statistics, University of Georgia (UGA), Athens, Georgia 2Department of Psychology, University of Georgia (UGA), Athens, Georgia 3Department of Neuroscience, University of Georgia (UGA), Athens, Georgia 4The Bio-Imaging Research Center, University of Georgia (UGA), Athens, Georgia 5UW Cardiovascular Research Center, University of Wisconsin School of Medicine and Public Health and theDepartment of Veterans Affairs (VA) Geriatric Research, Education and Clinical Center (GRECC), Madison, WI, USA 6Center for the Developing Brain, Child Mind Institute, 445 Park Ave, New York, NY 10022, USA r r 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 (gener- ating 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 antisac- cades, prosaccades (glancing toward a target), or fixation (maintaining gaze on a target). Principal obser- vations: 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 se- ries 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, prin- cipal component analysis (PCA), and K-means clustering.
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