title: Temporal lobe dysfunction in medication-naïve boys with attention-deficit/hyperactivity disorder during attention allocation and its relation to response variability.
abstract: BACKGROUND
  Patients with attention-deficit/hyperactivity disorder (ADHD) typically show fronto-striatal abnormalities during functions of cognitive control. In this study we investigate whether medication-naïve children with ADHD are impaired in temporo-parietal neural networks that mediate purely perceptual attention allocation to a behaviorally neutral oddball task. Furthermore, we explore the relationship between the neural substrates of attention allocation and response variability, typically increased in patients.
  
  
  METHODS
  Event-related functional magnetic resonance imaging was used to compare brain activation of 17 medication-naïve boys with ADHD with that of 18 handedness- and IQ-matched healthy comparison boys during a visual oddball task that required the same response to oddball and standard trials. Furthermore, to explore the relationship between behavioral dispersion and attention networks, regression analyses were conducted between response variability and brain activation networks.
  
  
  RESULTS
  Patients showed significantly reduced brain activation in left and right superior temporal lobes, basal ganglia, and posterior cingulate during the oddball versus standard contrast. The activation differences in superior temporal lobes correlated inversely with response variability in control subjects but not in patients with ADHD.
  
  
  CONCLUSIONS
  Brain abnormalities in patients with ADHD are not confined to fronto-striatal networks mediating executive functions but are also observed in temporo-striatal and cingulate regions during perceptive visual attention processes. Furthermore, temporal lobe dysfunction in the context of perceptual attention might be related to their behavioral problems with response variability.
authors.affiliation: Department of Child Psychiatry, Institute of Psychiatry, King's College, London, United Kingdom. k.rubia@iop.kcl.ac.uk
authors.forename: Katya
authors.initials: K
authors.lastname: Rubia
authors.forename: Anna B
authors.initials: AB
authors.lastname: Smith
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Brammer
authors.forename: Eric
authors.initials: E
authors.lastname: Taylor
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D001289:Attention Deficit Disorder with Hyperactivity / Q000473:pathology* / Q000503:physiopathology*; D016022:Case-Control Studies; D002648:Child; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007600:Judgment / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D011594:Psychometrics; D011930:Reaction Time / Q000502:physiology*; D013702:Temporal Lobe / Q000098:blood supply / Q000503:physiopathology*
chemical_list: D010100:Oxygen