Simultaneous visual sustained attention-discrimination and
goal-directed search are associated with excretion of catecholaminergic
metabolites in children with attention-deficit/hyperactivity disorder
Affiliations: Department of Pediatrics, University of Maryland
School of Medicine, Baltimore, MD, USA | Department of Pediatrics, Mayo Clinic, Rochester, MN,
USA | Department of Psychology, Loyola University,
Baltimore, MD, USA | Department of Pediatrics, Baylor College of Medicine;
Texas Children's Hospital, Houston, TX, USA | Department of Pediatrics, Wake Forest University,
Winston-Salem, NC, USA | Department of Psychiatry, University of California
School of Medicine, Neuropsychiatric Institute and Hospital, Los Angeles, CA,
USA
Note: [] Corresponding author: Dr. Antolin M. Llorente, University of
Maryland School of Medicine, 1708 West Rogers Avenue Baltimore, MD 21209, USA.
Tel.: +1 410 578 5080; Fax: +1 410 367 4197; E-mail: [email protected]
Abstract: The relationship between visual sustained attention-discrimination
and goal-directed search was evaluated using a visual discrimination and
exploration (goal-directed search) paradigm and urinary excretion of
catecholaminergic metabolites [dopamine (DA) and norepinephrine (NE)] in
6–12 year-old children (n=31) strictly selected and diagnosed with
attention-deficit/hyperactivity disorder (ADHD) using diagnostic criteria and
other objective indices. The Structured Clinical Interview (SCID) (DSM-IV) was
used to formally diagnose ADHD in children. A cognitive laboratory test was
used to assess visual sustained attention-discrimination and goal-directed
search (Children Color Trails Test 1 and 2). Urinary excretion of DA and NE
metabolites was measured via reversed high-pressure liquid chromatography
(HPLC). Pearson product-moment correlations were used to investigate the
relationship between visual sustained attention and goal-directed search and
urinary catecholamine metabolites of DA and NE. The present findings revealed a
positive and moderately significant relationship between visual sustained
attention and visual exploration and catecholaminergic metabolite levels of NE
and DA, according to expectation. Decreased visual sustained attention and
goal-directed search was associated with decreased DA and NE metabolite levels.
The present results are consistent with past research with children with ADHD
and studies with primates examining the intricate and respective interaction
between the Locus Coeruleus and visual sustained attention-discrimination and
the Ventral Tegmental Area and goal-directed search (visual exploration)
respectively modulated through NE and DA. Applied and theoretical issues
associated with the present findings also are discussed addressing recent
computer-generated analogues of action selection models within the context of
the extant findings.