Effortful and automatic memory: effects of dopamine.

With advancing age, there are changes in both cognitive functions and neurotransmitter metabolism. Dopamine plays a role in learning, memory, and related cognitive processes. We evaluated the effects of supplemental dopamine in precursor form (levodopa) on various aspects of memory in elderly normal volunteers in a controlled, double-blind study. Access to semantic memory and automatic processes were unaffected, but levodopa reliably facilitated effortful memory processing. Levodopa may be useful clinically in attenuating impairments in effortful cognitive tasks. Different neural systems probably mediate different forms of cognition.