“Methylphenidate Enhances Working Memory by Modulating Discrete Frontal and Parietal Lobe Regions in the Human Brain”, 2000-03-15 (; backlinks):
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 199925ya; Riordan et al 199925ya) and also in normal human volunteers on tasks sensitive to frontal lobe damage, including aspects of spatial working-memory (SWM) performance (Elliott et al 199727ya).
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.
[Keywords: cognition, dopamine, humans, methylphenidate, neuroimaging, Ritalin, stimulant, working memory]