title: A parietal biomarker for ADHD liability: as predicted by the distributed effects perspective model of ADHD.
abstract: BACKGROUND
  We previously hypothesized that poor task-directed sensory information processing should be indexed by increased weighting of right hemisphere (RH) biased attention and visuo-perceptual brain functions during task operations and have demonstrated this phenotype in ADHD across multiple studies, using multiple methodologies. However, in our recent distributed effects model of ADHD, we surmised that this phenotype is not ADHD specific, but rather more broadly reflective of any circumstance that disrupts the induction and maintenance of an emergent task-directed neural architecture. Under this view, increased weighting of RH-biased attention and visuo-perceptual brain functions is expected to generally index neurocognitive sets that are not optimized for task-directed thought and action, and when durable expressed, liability for ADHD.
  
  
  METHODS
  The current study tested this view by examining whether previously identified rightward parietal EEG asymmetry in ADHD was associated with common ADHD characteristics and comorbidities [i.e., ADHD risk factors (RFs)].
  
  
  RESULTS
  Barring one exception (non-right handedness), we found that it was. Rightward parietal asymmetry (RPA) was associated with carrying the DRD4-7R risk allele, being male, having mood disorder, and having anxiety disorder. However, differences in the specific expression of RPA were observed, which are discussed in relation to possible unique mechanisms underlying ADHD liability in different ADHD RFs.
  
  
  CONCLUSIONS
  Rightward parietal asymmetry appears to be a durable feature of ADHD liability, as predicted by the Distributed Effects Perspective Model of ADHD. Moreover, variability in the expression of this phenotype may shed light on different sources of ADHD liability.
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles Semel Institute for Neuroscience and Human Behavior , Los Angeles, CA , USA.
authors.forename: T Sigi
authors.initials: TS
authors.lastname: Hale
authors.affiliation: Department of Psychology, University of California Los Angeles , Los Angeles, CA , USA.
authors.forename: Joshua F
authors.initials: JF
authors.lastname: Wiley
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles Semel Institute for Neuroscience and Human Behavior , Los Angeles, CA , USA.
authors.forename: Susan L
authors.initials: SL
authors.lastname: Smalley
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles Semel Institute for Neuroscience and Human Behavior , Los Angeles, CA , USA.
authors.forename: Kelly L
authors.initials: KL
authors.lastname: Tung
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles Semel Institute for Neuroscience and Human Behavior , Los Angeles, CA , USA.
authors.forename: Olivia
authors.initials: O
authors.lastname: Kaminsky
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles Semel Institute for Neuroscience and Human Behavior , Los Angeles, CA , USA.
authors.forename: James J
authors.initials: JJ
authors.lastname: McGough
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles Semel Institute for Neuroscience and Human Behavior , Los Angeles, CA , USA.
authors.forename: Ashwin M
authors.initials: AM
authors.lastname: Jaini
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles Semel Institute for Neuroscience and Human Behavior , Los Angeles, CA , USA.
authors.forename: Sandra K
authors.initials: SK
authors.lastname: Loo
keywords: ADHD; DRD4; asymmetry; attention; laterality; liability; parietal; risk factors