The effects of methylphenidate on neural systems of attention in attention deficit hyperactivity disorder.
OBJECTIVE
Recent studies have suggested that attention deficit hyperactivity disorder (ADHD) is associated with abnormalities in basal ganglia and prefrontal cortical functioning. However, these studies have primarily relied upon cognitive tasks that reflect impulse control rather than attentional mechanisms.


METHODS
The authors used functional magnetic resonance imaging to investigate the neural correlates of selective and divided attention in a randomized, double-blind, placebo-controlled pharmacological challenge with methylphenidate in 15 adolescents with ADHD (ages 14-17), eight adolescents with reading disorder (ages 12-17), and four adolescents with both reading disorder and ADHD (ages 14-18) who were scanned during both a methylphenidate and a placebo session. Fourteen healthy comparison subjects (ages 12-20) who were not given methylphenidate served as the primary comparison group.


RESULTS
During the divided attention task, unmedicated subjects with ADHD or reading disorder recruited the left ventral basal ganglia significantly less than the healthy comparison subjects. Methylphenidate led to an increase in activation in this region but had no effect on task performance. Subjects with ADHD also recruited the middle temporal gyrus significantly less than the comparison subjects, but methylphenidate did not have a direct effect on activation in this region.


CONCLUSIONS
These results suggest that ADHD is associated with abnormal processing in attentional networks, with specific dysfunction in striatal circuitry. Methylphenidate may act to normalize activity within this network.
Shafritz
Keith M
KM
Brain Imaging and Analysis Center, Duke University Medical Center, Box 3918, Durham, NC 27710, USA. keith.shafritz@aya.yale.edu
Marchione
Karen E
KE
Gore
John C
JC
Shaywitz
Sally E
SE
Shaywitz
Bennett A
BA
D000293:Adolescent; D001288:Attention / Q000187:drug effects*; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy* / Q000503:physiopathology; D001479:Basal Ganglia / Q000187:drug effects* / Q000503:physiopathology; D000697:Central Nervous System Stimulants / Q000494:pharmacology / Q000627:therapeutic use*; D003342:Corpus Striatum / Q000187:drug effects / Q000503:physiopathology; D004311:Double-Blind Method; D004410:Dyslexia / Q000188:drug therapy / Q000503:physiopathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008774:Methylphenidate / Q000494:pharmacology / Q000627:therapeutic use*; D009434:Neural Pathways / Q000187:drug effects / Q000503:physiopathology; D010919:Placebos; D017397:Prefrontal Cortex / Q000187:drug effects* / Q000503:physiopathology; D011597:Psychomotor Performance / Q000187:drug effects / Q000502:physiology
D000697:Central Nervous System Stimulants; D010919:Placebos; D008774:Methylphenidate