RESULTS The fMRI analysis showed that methylpheni date significantly enhanced activation in bilateral inferior frontal cortex (IFC)/insula during inhibition and time discrimination but had no effect on working memory networks .
The meta- analysis , including 14 fMRI data sets and 212 children with ADHD , showed that stimulants most consistently enhanced right IFC/insula activation , which also remained for a subgroup analysis of methylpheni date effects alone .
A more lenient threshold also revealed increased putamen activation .
CONCLUSIONS Psychostimulants most consistently increase right IFC/insula activation , which are key areas of cognitive control and also the most replicated neurocognitive dysfunction in ADHD .
These neurocognitive effects may underlie their positive clinical effects
BACKGROUND Psychostimulant medication , most commonly the catecholamine agonist methylpheni date , is the most effective treatment for attention-deficit/hyperactivity disorder ( ADHD ) .
However , relatively little is known on the mechanisms of action .
Acute effects on brain function can eluci date underlying neurocognitive effects .
We tested methylpheni date effects relative to placebo in functional magnetic resonance imaging ( fMRI ) during three disorder-relevant tasks in medication-naïve ADHD adolescents .
In addition , we conducted a systematic review and meta- analysis of the fMRI findings of acute stimulant effects on ADHD brain function .
Functional magnetic resonance imaging of methylphenidate and placebo in attention-deficit/hyperactivity disorder during the multi-source interference task.
CONTEXT Previous studies have reported hypofunction , structural abnormalities , and biochemical abnormalities of the dorsal anterior midcingulate cortex ( daMCC ) in attention-deficit/hyperactivity disorder ( ADHD ) . Stimulant medications are effective treatments for ADHD , but their neural effects have not been fully characterized . OBJECTIVE To determine whether the methylpheni date hydrochloride osmotic-release oral system ( OROS ) would increase functional magnetic resonance imaging ( fMRI ) activation , compared with placebo , in the daMCC and other frontoparietal regions subserving attention during the Multi- Source Interference Task ( MSIT ) . DESIGN R and omized , placebo-controlled , 6-week , before-after fMRI study . SETTING Academic medical center ambulatory clinic . PATIENTS Twenty-one adults with ADHD r and omized to 6 weeks of treatment with methylpheni date OROS ( n = 11 ) or placebo ( n = 10 ) . INTERVENTIONS Patients underwent fMRI twice while performing the MSIT ( scan 1 at baseline and scan 2 at 6 weeks ) . MAIN OUTCOME MEASURES Group-averaged , r and om-effects , repeated- measures , general linear model analyses were used to compare daMCC ( and whole-brain ) fMRI activation during the MSIT . Individual-based daMCC volume-of-interest confirmatory analyses and behavioral data are also presented . RESULTS Performance and baseline fMRI measures in the daMCC and other a priori brain regions did not differ between groups . Group comparisons showed a group x scan interaction and t test confirmation of higher activation in the daMCC at 6 weeks in the methylpheni date OROS group than in the placebo group ( P < 1 x 10(-4 ) , cluster corrected for multiple comparisons ) . Individual daMCC volume-of-interest analyses confirmed group-averaged findings and suggested that daMCC activity might be related to clinical response . Methylpheni date OROS also produced higher activation in the dorsolateral prefrontal cortex and the parietal cortex at 6 weeks . CONCLUSION Methylpheni date OROS increased daMCC activation during the MSIT and may act , in part , by normalizing daMCC hypofunction in ADHD
RESULTS The fMRI analysis showed that methylpheni date significantly enhanced activation in bilateral inferior frontal cortex (IFC)/insula during inhibition and time discrimination but had no effect on working memory networks .
The meta- analysis , including 14 fMRI data sets and 212 children with ADHD , showed that stimulants most consistently enhanced right IFC/insula activation , which also remained for a subgroup analysis of methylpheni date effects alone .
A more lenient threshold also revealed increased putamen activation .
CONCLUSIONS Psychostimulants most consistently increase right IFC/insula activation , which are key areas of cognitive control and also the most replicated neurocognitive dysfunction in ADHD .
These neurocognitive effects may underlie their positive clinical effects
BACKGROUND Psychostimulant medication , most commonly the catecholamine agonist methylpheni date , is the most effective treatment for attention-deficit/hyperactivity disorder ( ADHD ) .
However , relatively little is known on the mechanisms of action .
Acute effects on brain function can eluci date underlying neurocognitive effects .
We tested methylpheni date effects relative to placebo in functional magnetic resonance imaging ( fMRI ) during three disorder-relevant tasks in medication-naïve ADHD adolescents .
In addition , we conducted a systematic review and meta- analysis of the fMRI findings of acute stimulant effects on ADHD brain function .