Neuronal mechanisms underlying attention deficit hyperactivity disorder: the influence of arousal on prefrontal cortical function.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing preclinical mechanisms and clinical observations without systematic review methodology
PubMed 18591484 · doi:10.1196/annals.1417.007
What was done
Narrative review synthesizing findings from neuropsychological and neuroimaging studies in humans, observations of patients with cortical lesions, and electrophysiological and pharmacological research in animals examining prefrontal cortex function and catecholaminergic mechanisms in ADHD.
What was found
No quantitative data or pooled statistics were reported in the abstract. Prefrontal cortex alterations, particularly in the right hemisphere and frontostriatal-cerebellar connections, associate with impaired behavioral inhibition, working memory, and attention regulation. In animal models, prefrontal cognitive control weakens with either insufficient or excessive catecholamine release. Norepinephrine enhances neural signals via postsynaptic alpha2A adrenoceptors, while dopamine decreases noise through modest D1 receptor stimulation. Blocking alpha2 receptors in monkey prefrontal cortex reproduces ADHD-like symptoms of impaired working memory, increased impulsivity, and locomotor hyperactivity.
Why it matters
The review provides a mechanistic model explaining how catecholamine signaling in prefrontal networks modulates cognitive control and how ADHD medications may achieve therapeutic effects by optimizing alpha2A and D1 receptor stimulation.
Limits
This is a narrative review with no primary data, sample sizes, or quantitative effect sizes reported in the abstract. Key mechanistic findings rely on animal models and lesion studies, which may not fully capture the clinical heterogeneity of human ADHD.
Cited by
- supports Catecholamines (dopamine, norepinephrine, and epinephrine) are released in the brain and body during high-arousal situations.