The role of prefrontal cortex in working memory: Examining the contents of consciousness
Philosophical Transactions of the Royal Society B: Biological Sciences. 1998-11-29; 353(1377): 1819-1828
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1. Philos Trans R Soc Lond B Biol Sci. 1998 Nov 29;353(1377):1819-28.
The role of prefrontal cortex in working memory: examining the contents of
Courtney SM(1), Petit L, Haxby JV, Ungerleider LG.
(1)Laboratory of Brain and Cognition, National Institute of Mental Health,
Bethesda, MD 20892-1366, USA.
Working memory enables us to hold in our ‘mind’s eye’ the contents of our
conscious awareness, even in the absence of sensory input, by maintaining an
active representation of information for a brief period of time. In this review
we consider the functional organization of the prefrontal cortex and its role in
this cognitive process. First, we present evidence from brain-imaging studies
that prefrontal cortex shows sustained activity during the delay period of visual
working memory tasks, indicating that this cortex maintains on-line
representations of stimuli after they are removed from view. We then present
evidence for domain specificity within frontal cortex based on the type of
information, with object working memory mediated by more ventral frontal regions
and spatial working memory mediated by more dorsal frontal regions. We also
propose that a second dimension for domain specificity within prefrontal cortex
might exist for object working memory on the basis of the type of representation,
with analytic representations maintained preferentially in the left hemisphere
and image-based representations maintained preferentially in the right
hemisphere. Furthermore, we discuss the possibility that there are prefrontal
areas brought into play during the monitoring and manipulation of information in
working memory in addition to those engaged during the maintenance of this
information. Finally, we consider the relationship of prefrontal areas important
for working memory, both to posterior visual processing areas and to prefrontal
areas associated with long-term memory.
PMID: 9854254 [Indexed for MEDLINE]