The prefrontal cortex plays a critical role in working memory, the active maintenance of information for brief periods of time for guiding future motor and cognitive processes. Two competing models have emerged to account for the growing human and non-human primate literature examining the functional neuroanatomy of working memory. One theory holds that the lateral frontal cortex plays a domain-specific role in working memory with the dorsolateral and ventrolateral cortical regions supporting working memory for spatial and non-spatial material, respectively. Alternatively, the lateral frontal cortex may play a process-specific role with the more dorsal regions becoming recruited whenever active manipulation or monitoring of information in working memory becomes necessary. Many working memory tasks do not allow for direct tests of these competing models. The present study used a novel self-ordered working memory task and positron emission tomography to identify whether dorsal or ventral lateral cortical areas are recruited during a working memory task that required extensive monitoring of non-spatial information held within working memory. We observed increased blood flow in the right dorsolateral, but not ventrolateral, prefrontal cortex. Increases in blood flow in the dorsolateral region correlated strongly with task performance. Thus, the results support the process-specific hypothesis. Copyright (C) 2000 Elsevier Science Ltd.
Bibliographical noteFunding Information:
This work was supported by the Department of Veterans Affairs, the Alzheimer’s Association, and NARSAD. We thank E. Darcy Burgund and Chad Marsolek, University of Minnesota, Department of Psychology, for the 3D objects, Thomas Zielund, Minnesota Twin Family Study, for computer programming, and the staff of the VAMC PET Imaging Service for technical assistance. CEC was supported by Eva O. Miller Fellowship and NIMH (MH 49738), and DHZ by NRSA (1 F32 MH11641-01A1).
- Dorsolateral prefrontal cortex
- Positron emission tomography
- Self-ordered task
- Ventrolateral prefrontal cortex
- Working memory