The Journal of Neuroscience, 2000, 20:RC65:1-6
RAPID COMMUNICATION
Methylphenidate Enhances Working Memory by Modulating Discrete
Frontal and Parietal Lobe Regions in the Human Brain
Mitul A.
Mehta1,
Adrian
M.
Owen3,
Barbara J.
Sahakian1,
Nahal
Mavaddat1,
John D.
Pickard2, and
Trevor W.
Robbins4
1 University of Cambridge, Department of Psychiatry,
and 2 Wolfson Brain Imaging Centre, Addenbrooke's
Hospital, Cambridge, CB2 2QQ, United Kingdom, 3 Medical
Research Council Cognition and Brain Sciences Unit, Cambridge, CB2 2EF,
United Kingdom, and 4 University of Cambridge, Department
of Experimental Psychology, Downing Site, Cambridge CB2 3EB, United
Kingdom
The indirect catecholamine agonist methylphenidate (Ritalin) is the
drug treatment of choice in attention deficit/hyperactivity disorder
(AD/HD), one of the most common behavioral disorders of childhood
(DSM-IV), although symptoms may persist into adulthood. Methylphenidate can enhance cognitive performance in adults and children diagnosed with AD/HD (Kempton et al., 1999;
Riordan et al., 1999) and also in normal human volunteers on
tasks sensitive to frontal lobe damage, including aspects of spatial
working memory (SWM) performance (Elliott et al., 1997). The present
study investigated changes in regional cerebral blood flow (rCBF)
induced by methylphenidate during performance of a self-ordered SWM
task to define the neuroanatomical loci of the beneficial effect of the
drug. The results show that the methylphenidate-induced improvements in
working memory performance occur with task-related reductions in rCBF
in the dorsolateral prefrontal cortex and posterior parietal
cortex. The beneficial effects of methylphenidate on working memory
were greatest in the subjects with lower baseline working memory
capacity. This is to our knowledge the first demonstration of a
localization of a drug-induced improvement in SWM performance in humans
and has relevance for understanding the treatment of AD/HD.
Key words:
cognition; dopamine; humans; methylphenidate; neuroimaging; Ritalin; stimulant; working memory
Copyright © 2000 Society for Neuroscience 0270-6474/00/$05.00/0