Differential Patterns of Brain Activation over Time in Adolescents with and without Attention Deficit Hyperactivity Disorder (ADHD) during Performance of a Sustained Attention Task

Abstract

Objective Recent morphometric studies suggest that children with ADHD may demonstrate differential or delayed brain development than children without ADHD. Further, the regions that appear to be affected are regions that control attention and executive functioning. This study examines the developmental course of brain activation patterns during an attention task. Method Ten adolescents with ADHD and 14 normal controls performed a continuous performance task twice one year apart. fMRI scans were collected at each timepoint. Results In the absence of performance differences, children with ADHD and normal controls activated frontal-parietal regions while performing an attention task at initial testing. One year later, the normal control group evidenced no task-related areas of activation while performing the same task while the children with ADHD showed less activation at the second testing but continued to evidence task-related activations in bilateral frontal areas and left parietal lobe at the time of the second testing. In particular, children with ADHD appeared to require continued use of the right middle frontal gyrus during administration of testing one year apart while normal controls did not activate this region at the time of the second testing. Conclusions Children with ADHD appear to maintain the use of right prefrontal regions during attentional tasks beyond what is observed among normal controls. Given observed cortical thinning in corresponding brain regions, future research must address the recipocal effects of volumetric reductions and a continued need for using these regions to perform basic attentional tasks.

Atypical Default Network Connectivity in Youth with Attention-Deficit/Hyperactivity Disorder

“…The present findings, which show reduced connectivity within this network in ADHD compared to age matched controls is, in part, consistent with, and may renew assertions that ADHD is a disorder of delayed neural development (59-62). Indeed, while numbers vary and largely depend on diagnostic criteria, many children with ADHD appear to improve with age (63).…”

1H MRSI of middle frontal gyrus in pediatric ADHD

“…Using resting-state BOLD fMRI, Yang et al (2011) calculated lower amplitude of low-frequency fluctuations in pediatric ADHD patients than in controls in bilateral anterior and posterior middle cingulate cortex and specifically in right middle frontal cortex. In a longitudinal activation BOLD fMRI study using the continuous performance task (Epstein et al, 2009), the right middle frontal cortex was unique among brain regions in that local BOLD effect increased for the adolescent ADHD sample and decreased for the control sample at one-year follow-up relative to baseline.Hence, our MRSI findings of exclusively right-hemisphere neurometabolite depletion meet an expectation of specific right-sided effects emerging from prior neurocognitive and neuroimaging work in ADHD.…”

Hypoactivation in right inferior frontal cortex is specifically associated with motor response inhibition in adult ADHD

“…Moreover, varied results whilst comparing control and patient groups have been noted in the inferior frontal cortex (IFC) [Carmona et al, 2012]. Additional inconsistent results have been reported in the cerebellum and parietal cortex [Dillo et al, 2010;Epstein et al, 2009;Hale et al, 2007].…”