Modulation of steady state functional connectivity in the default mode and working memory networks by cognitive load

Authors

  • Allen T. Newton,

    Corresponding author
    1. Vanderbilt University Institute of Imaging Science, Nashville, TN, 37232, USA
    2. Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, 37232, USA
    • Vanderbilt University Institute of Imaging Science, 1161 21st Avenue South, Medical Center North, AA-1105, Nashville, TN 37232-2310

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  • Victoria L. Morgan,

    1. Vanderbilt University Institute of Imaging Science, Nashville, TN, 37232, USA
    2. Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, 37232, USA
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  • Baxter P. Rogers,

    1. Vanderbilt University Institute of Imaging Science, Nashville, TN, 37232, USA
    2. Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, 37232, USA
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  • John C. Gore

    1. Vanderbilt University Institute of Imaging Science, Nashville, TN, 37232, USA
    2. Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, 37232, USA
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Abstract

Interregional correlations between blood oxygen level dependent (BOLD) magnetic resonance imaging (fMRI) signals in the resting state have been interpreted as measures of connectivity across the brain. Here we investigate whether such connectivity in the working memory and default mode networks is modulated by changes in cognitive load. Functional connectivity was measured in a steady-state verbal identity N-back task for three different conditions (N = 1, 2, and 3) as well as in the resting state. We found that as cognitive load increases, the functional connectivity within both the working memory the default mode network increases. To test whether functional connectivity between the working memory and the default mode networks changed, we constructed maps of functional connectivity to the working memory network as a whole and found that increasingly negative correlations emerged in a dorsal region of the posterior cingulate cortex. These results provide further evidence that low frequency fluctuations in BOLD signals reflect variations in neural activity and suggests interaction between the default mode network and other cognitive networks. Hum Brain Mapp, 2010. © 2010 Wiley-Liss, Inc.

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