Impairment of functional integration of the default mode network correlates with cognitive outcome at three months after stroke

  • Rosalia Dacosta‐Aguayo
    Department of Psychiatry and Clinical Psychobiology University of Barcelona Barcelona Spain
  • Manuel Graña
    Group of Computational Intelligence Department of CCIA University of the Basque Country UPV/EHU San Sebastian Spain
  • Yasser Iturria‐Medina
    McConnell Brain Imaging Centre Montreal Neurological Institute Montreal Quebec Canada
  • Marina Fernández‐Andújar
    Department of Psychiatry and Clinical Psychobiology University of Barcelona Barcelona Spain
  • Elena López‐Cancio
    Department of Neurosciences Hospital Germans Trias i Pujol, Autonomous University of Barcelona Badalona Barcelona Spain
  • Cynthia Cáceres
    Department of Neurosciences Hospital Germans Trias i Pujol, Autonomous University of Barcelona Badalona Barcelona Spain
  • Núria Bargalló
    Radiology Department Image Diagnosis Center, Hospital Clínic Barcelona Spain
  • Maite Barrios
    Department of Methodology of Behavioral Sciences University of Barcelona Spain
  • Immaculada Clemente
    Department of Psychiatry and Clinical Psychobiology University of Barcelona Barcelona Spain
  • Pera Toran
    Institute of Biomedical Research August Pi i Sunyer (IDIBAPS) Barcelona Spain
  • Rosa Forés
    Institute of Biomedical Research August Pi i Sunyer (IDIBAPS) Barcelona Spain
  • Antoni Dávalos
    Department of Neurosciences Hospital Germans Trias i Pujol, Autonomous University of Barcelona Badalona Barcelona Spain
  • Tibor Auer
    MRC Cognition and Brain Sciences Unit Cambridge England
  • Maria Mataró
    Department of Psychiatry and Clinical Psychobiology University of Barcelona Barcelona Spain

抄録

<jats:title>Abstract</jats:title><jats:p>Resting‐state studies conducted with stroke patients are scarce. The study of brain activity and connectivity at rest provides a unique opportunity for the investigation of brain rewiring after stroke and plasticity changes. This study sought to identify dynamic changes in the functional organization of the default mode network (DMN) of stroke patients at three months after stroke. Eleven patients (eight male and three female; age range: 48–72) with right cortical and subcortical ischemic infarctions and 17 controls (eleven males and six females; age range: 57–69) were assessed by neurological and neuropsychological examinations and scanned with resting‐state functional magnetic ressonance imaging. First, we explored group differences in functional activity within the DMN by means of probabilistic independent component analysis followed by a dual regression approach. Second, we estimated functional connectivity between 11 DMN nodes both locally by means of seed‐based connectivity analysis, as well as globally by means of graph‐computation analysis. We found that patients had greater DMN activity in the left precuneus and the left anterior cingulate gyrus when compared with healthy controls (<jats:italic>P</jats:italic> < 0.05 family‐wise error corrected). Seed‐based connectivity analysis showed that stroke patients had significant impairment (<jats:italic>P</jats:italic> = 0.014; threshold = 2.00) in the connectivity between the following five DMN nodes: left superior frontal gyrus (lSFG) and posterior cingulate cortex (<jats:italic>t</jats:italic> = 2.01); left parahippocampal gyrus and right superior frontal gyrus (<jats:italic>t</jats:italic> = 2.11); left parahippocampal gyrus and lSFG (<jats:italic>t</jats:italic> = 2.39); right parietal and lSFG (<jats:italic>t</jats:italic> = 2.29). Finally, mean path length obtained from graph‐computation analysis showed positive correlations with semantic fluency test (<jats:italic>r</jats:italic> <jats:sub>s</jats:sub> = 0.454; <jats:italic>P</jats:italic> = 0.023), phonetic fluency test (<jats:italic>r</jats:italic> <jats:sub>s</jats:sub> = 0.523; <jats:italic>P</jats:italic> = 0.007) and the mini mental state examination (<jats:italic>r</jats:italic> <jats:sub>s</jats:sub> = 0.528; <jats:italic>P</jats:italic> = 0.007). In conclusion, the ability to regulate activity of the DMN appears to be a central part of normal brain function in stroke patients. Our study expands the understanding of the changes occurring in the brain after stroke providing a new avenue for investigating lesion‐induced network plasticity. <jats:italic>Hum Brain Mapp 36:577–590, 2015</jats:italic>. © <jats:bold>2014 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.</jats:bold> </jats:p>

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