title: Reduced prefrontal efficiency for visuospatial working memory in attention-deficit/hyperactivity disorder.
abstract: OBJECTIVE
  Visuospatial working memory impairments have been implicated in the pathophysiology of attention-deficit/hyperactivity disorder (ADHD). However, most ADHD research has focused on the neural correlates of nonspatial mnemonic processes. This study examined brain activation and functional connectivity for visuospatial working memory in youth with and without ADHD.
  
  
  METHODS
  Twenty-four youth with ADHD and 21 age- and sex-matched healthy controls were scanned with functional magnetic resonance imaging while performing an N-back test of working memory for spatial position. Block-design analyses contrasted activation and functional connectivity separately for high (2-back) and low (1-back) working memory load conditions versus the control condition (0-back). The effect of working memory load was modeled with linear contrasts.
  
  
  RESULTS
  The 2 groups performed comparably on the task and demonstrated similar patterns of frontoparietal activation, with no differences in linear gains in activation as working memory load increased. However, youth with ADHD showed greater activation in the left dorsolateral prefrontal cortex (DLPFC) and left posterior cingulate cortex (PCC), greater functional connectivity between the left DLPFC and left intraparietal sulcus, and reduced left DLPFC connectivity with left midcingulate cortex and PCC for the high load contrast compared to controls (p < .01; k > 100 voxels). Reanalysis using a more conservative statistical approach (p < .001; k > 100 voxels) yielded group differences in PCC activation and DLPFC-midcingulate connectivity.
  
  
  CONCLUSIONS
  Youth with ADHD show decreased efficiency of DLPFC for high-load visuospatial working memory and greater reliance on posterior spatial attention circuits to store and update spatial position than healthy control youth. Findings should be replicated in larger samples.
authors.affiliation: Icahn School of Medicine at Mount Sinai School of Medicine, New York. Electronic address: ac.bedard@mssm.edu.
authors.forename: Anne-Claude V
authors.initials: AC
authors.lastname: Bédard
authors.affiliation: Icahn School of Medicine at Mount Sinai School of Medicine, New York.
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Newcorn
authors.affiliation: Icahn School of Medicine at Mount Sinai School of Medicine, New York; Purchase College of the State University of New York.
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Clerkin
authors.affiliation: Icahn School of Medicine at Mount Sinai School of Medicine, New York.
authors.forename: Beth
authors.initials: B
authors.lastname: Krone
authors.affiliation: Icahn School of Medicine at Mount Sinai School of Medicine, New York; Queens College of the City University of New York.
authors.forename: Jin
authors.initials: J
authors.lastname: Fan
authors.affiliation: Icahn School of Medicine at Mount Sinai School of Medicine, New York; Queens College of the City University of New York.
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Halperin
authors.affiliation: Icahn School of Medicine at Mount Sinai School of Medicine, New York.
authors.forename: Kurt P
authors.initials: KP
authors.lastname: Schulz
mesh_terms: D000293:Adolescent; D001288:Attention / Q000502:physiology*; D001289:Attention Deficit Disorder with Hyperactivity / Q000503:physiopathology*; D002648:Child; D063132:Connectome; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D017397:Prefrontal Cortex / Q000503:physiopathology*; D013028:Space Perception / Q000502:physiology*
keywords: ADHD; children; fMRI; prefrontal cortex; spatial working memory