ABSTRACT
OBJECTIVE: In this study, we aimed to explore how cues signaling rewards and feedbacks about rewards are processed in ADHD. METHOD: Inside the scanner, 16 healthy children and 19 children with ADHD completed a spatial attention paradigm where cues informed about the availability of reward and feedbacks were provided about the earned reward. RESULTS: In ventral anterior thalamus (VA), the controls exhibited greater activation in response to reward-predicting cues, as compared with no-reward cues, whereby in the ADHD group, the reverse pattern was observed (nonreward > reward). For feedbacks; absence of rewards produced greater activation than presence in the left caudate and frontal eye field for the control group, whereas for the ADHD group, the reverse pattern was again observed (reward > nonreward). DISCUSSION: The present findings indicate that ADHD is associated with difficulty integrating reward contingency information with the orienting and regulatory phases of attention.
Subject(s)
Attention Deficit Disorder with Hyperactivity/physiopathology , Reward , Attention/physiology , Child , Cues , Feedback, Psychological/physiology , Female , Frontal Lobe , Humans , Magnetic Resonance Imaging , Male , Mental Processes/physiology , Motivation/physiologyABSTRACT
OBJECTIVE: Several studies report that ADHD is associated with reduced gray matter (GM), whereas others report no differences in GM volume between ADHD patients and controls, and some even report more GM volume in individuals with ADHD. These conflicting findings suggest that reduced GM is not a universal finding in ADHD, and that more research is needed to delineate with greater accuracy the range of GM alterations. METHOD: The present study aimed to identify GM alterations in ADHD using pediatric templates. 19 drug-naïve ADHD patients and 18 controls, all aged 7 to 14 years, were scanned using magnetic resonance imaging. RESULTS: Relative to the controls, the ADHD patients had more GM, predominantly in the precentral and supplementary motor areas. Moreover, there were positive correlations between GM volume in these areas and ADHD scale scores. CONCLUSION: The clinical and pathophysiological significance of increased GM in the motor areas remains to be elucidated by additional research.
