Elsevier

Brain and Cognition

Volume 41, Issue 1, October 1999, Pages 66-86
Brain and Cognition

Regular Article
Maintenance versus Manipulation of Information Held in Working Memory: An Event-Related fMRI Study

https://doi.org/10.1006/brcg.1999.1096Get rights and content
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Abstract

One model of the functional organization of lateral prefrontal cortex (PFC) in primates posits that this region is organized in a dorsal/ventral fashion subserving spatial and object working memory, respectively. Alternatively, it has been proposed that a dorsal/ventral subdivision of lateral PFC instead reflects the type of processing performed upon information held in working memory. We tested this hypothesis using an event-related fMRI method that can discriminate among functional changes occurring during temporally separated behavioral subcomponents of a single trial. Subjects performed a delayed-response task with two types of trials in which they were required to: (1) retain a sequence of letters across the delay period (maintenance) or (2) reorder the sequence into alphabetical order across the delay period (manipulation). In each subject, activity during the delay period was found in both dorsolateral and ventrolateral PFC in both types of trials. However, dorsolateral PFC activity was greater in manipulation trials. These findings are consistent with the processing model of the functional organization of working memory in PFC.

Keywords

Key Words: functional MRI
working memory
prefrontal cortex

Cited by (0)

This work was supported by the Charles A. Dana Foundation, American Federation for Aging Research, and NIH Grants NS01762 and AG13483. We thank Eric Zarahn and Geoff Aguirre for their support on this project.

Address all correspondence to Mark D'Esposito, Department of Neurology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA 19104-4283. Fax: (215) 349-5579. E-Mail: [email protected]. Website: cortex.med.upenn.edu.