Methylphenidate and intracortical excitability: opposite effects in healthy subjects and attention-deficit hyperactivity disorder.
OBJECTIVE
To test the effects of a standard dosage of the psychostimulant methylphenidate (MPH) - which significantly enhances intracortical inhibition but had no effects on intracortical facilitation in children with attention-deficit hyperactivity disorder (ADHD) - on intracortical excitability in healthy subjects.


METHODS
In 12 healthy subjects, aged 20-40 years, intracortical inhibition and facilitation were investigated before and 70 min after the intake of 10 mg MPH using the technique of transcranial magnetic stimulation (TMS) with the paired-stimulus paradigm.


RESULTS
In comparison of the two TMS measurements, a significant enhancement in intracortical facilitation but no effects on intracortical inhibition could be stated under MPH administration.


CONCLUSIONS
This study provides first evidence for opposite effects of MPH on intracortical excitability in healthy adult subjects showing enhanced intracortical facilitation in contrast to ADHD children in whom enhanced intracortical inhibition has recently been shown.
Moll
G H
GH
Child & Adolescent Psychiatry, University of Erlangen, Erlangen, Germany.
Heinrich
H
H
Rothenberger
A
A
D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy*; D000697:Central Nervous System Stimulants / Q000494:pharmacology* / Q000627:therapeutic use*; D002540:Cerebral Cortex / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000494:pharmacology* / Q000627:therapeutic use*
D000697:Central Nervous System Stimulants; D008774:Methylphenidate