Structural Brain Changes
The pathogenesis of ADHD impacts grey matter in the brain in this way.
What is decreased grey matter volume?
Hyperactivity, such as climbing on furniture during school, is most strongly associated with dysfunction of this network.
What is the motor control network?
This is the primary protein blocked by methylphenidate, leading to increased dopamine concentrations in the synapse.
What is the dopamine transporter (DAT)?
Reduced volume in this prefrontal region is thought to contribute to deficits in executive function and working memory in ADHD.
What is the dorsolateral prefrontal cortex (DLPFC)?
This network directs attention toward goal-directed tasks and shows reduced activation in ADHD.
What is the Frontoparietal Network?
Think top-down attention, working memory, executive control.
The efficacy of guanfacine in ADHD stems from its ability to mimic the effects of this neurotransmitter at postsynaptic α2A receptors in the prefrontal cortex.
What is norepinephrine?
A landmark 2007 neuroimaging study demonstrated that children with ADHD reach this developmental milestone approximately 3 years later than controls.
What is peak cortical thickness?
Immediate gratification is most closely associated with dysfunction in this ADHD circuit.
Reward Circuit
(Cortico-limbic network)
True or False: Functional imaging studies consistently demonstrate increased dopamine transporter (DAT) binding in individuals with ADHD.
Answer: False. While some studies report increased DAT binding (up to 70%), others have found no difference, and medication status may account for some discrepancies.
Structural MRI studies consistently show that individuals with ADHD have brains that are approximately 3–5% smaller overall, with the most reproducible regional finding involving decreased volume in this structure.
What is the striatum?
Your attending suddenly calls your name during rounds. This network allows you to rapidly shift attention to that unexpected but relevant stimulus.
What is the Ventral Attention Network?
bottom-up attention
How are GABA and Glutamate concentrations impacted in ADHD?
In adults with ADHD, the rate of this structural brain change correlates with symptom severity.
What is cortical thinning?
The prefrontal cortex, basal ganglia, dorsal anterior cingulate, and right lateral cerebellum are key components of these networks.
What are the corticocerebellar and executive control networks?
Why can both undertreatment and overtreatment with stimulant medications worsen executive functioning in patients with ADHD?
Because dopamine and norepinephrine follow an inverted U-shaped dose-response in the prefrontal cortex, with both deficient and excessive signaling impairing function.