Frontostriatal Dysfunction During Decision Making in Attention-Deficit/Hyperactivity Disorder and...

Area of Science:

• Neuroscience
• Developmental Psychology
• Computational Psychiatry

Background:

• Attention-deficit/hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD) are common neurodevelopmental disorders.
• Understanding their distinct and shared computational and neural mechanisms is crucial for targeted interventions.

Purpose of the Study:

• To compare computational mechanisms and neurofunctional substrates in adolescents with ADHD and OCD during decision-making under ambiguity.
• To identify shared and disorder-specific neural correlates of decision-making deficits.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used with the Iowa Gambling Task in 16 boys with ADHD, 20 with OCD, and 20 controls (ages 12-18).
• Three-way analysis of covariance compared brain activation, and hierarchical Bayesian analysis modeled computational parameters.

Main Results:

• Both ADHD and OCD groups exhibited reduced choice consistency and reliance on reinforcement learning compared to controls.
• Shared underactivation in the ventral striatum (advantageous choices) and medial prefrontal cortex (losses) was observed.
• ADHD showed increased reward sensitivity and unique right putamen dysfunction, while OCD displayed disorder-specific underactivation in the ventromedial orbitofrontal cortex.

Conclusions:

• Shared deficits in using reward expectancies and medio-fronto-striato-limbic dysfunction underlie decision-making impairments in both disorders.
• Disorder-specific abnormalities in the ventromedial orbitofrontal cortex (OCD) and right putamen (ADHD) highlight unique neural pathways.
• These findings extend to decision-making under ambiguity, complementing previous research on inhibitory control deficits.