Methylphenidate enhances prepulse inhibition during processing of task-relevant
stimuli in attention-deficit/hyperactivity disorder.
Author(s): Ashare RL, Hawk LW Jr, Shiels K, Rhodes JD, Pelham WE Jr, Waxmonsky JG.
Affiliation(s): Department of Psychology, University at Buffalo, SUNY, Buffalo, New York
14260-4110, USA.
Publication date & source: 2010, Psychophysiology. , 47(5):838-45
ADHD is characterized by inattention, hyperactivity, and disinhibition, including
the inability to screen out distracting stimuli. Prepulse inhibition (PPI) of
startle indexes a related gating process and is enhanced during attended compared
to ignored stimuli. We predicted that PPI during attended stimuli would be
enhanced by the stimulant methylphenidate (MPH) and that this effect would be
moderated by baseline PPI. Children with ADHD (n=36) completed a baseline day and
a randomized, double-blind medication trial (placebo vs. sustained release MPH).
Bilateral startle eyeblink EMG was measured during a tone discrimination task.
MPH enhanced PPI during attended, but not during ignored stimuli. Extending
findings that pretreatment functioning moderates stimulant effects on PPI, this
effect tended to be inversely related to baseline PPI. These data fit with the
clinical literature on ADHD and the hypothesis that MPH enhances interference
control for important environmental stimuli.
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