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Postle BR, Berger JS, Taich AM, D'Esposito M.

Activity in Human Frontal Cortex Associated with Spatial Working Memory and Saccadic Behavior

fMRIDC Accession Number: 2-2000-1112R
Journal of Cognitive Neuroscience 2000 Nov ;12(suppl. 2): p.2-14
PubMed ID: 11506643 (off-site link)
 Study Meta-Data

We examined, with event-related fMRI, two hypotheses about the organization of human working memory function in frontal cortex: (1) that a region immediately anterior to the frontal eye fields (superior frontal cortex, SFC) is specialized for spatial working memory (Courtney et al., 1998); and 2) that dorsolateral prefrontal cortex (PFC) plays a privileged role in the manipulation of spatial stimuli held in working memory (Owen et al., 1996; Petrides, 1994). Our delayed-response task featured 2-D arrays of irregularly arranged squares that were highlighted serially in a random sequence. The Forward Memory condition required maintenance of the spatiotemporal sequence, the Manipulate Memory condition required reordering this sequence into a new spatially defined order, the Guided Saccade condition required saccades to highlighted squares in the array, but no memory, and the Free Saccade condition required self-paced, horizontal saccades. The comparison of fMRI signal intensity associated with 2-D saccade generation (Guided Saccades) versus fMRI signal intensity associated with the delay period of the working memory condition revealed no evidence for greater working memory-than saccade-related activity in SFC in any individual subject, nor at the level of the group, and greater 2-D saccade than delay-period activity in three of five subjects. These results fail to support the hypothesis that spatial working memory-related activity represented preferentially in a region of SFC anterior to the FEF (Courtney, et al., 1998). The comparison of maintenance vs. manipulation of spatiotemporal information in working memory revealed significantly greater activity associated with the latter in dorsolateral PFC, but not in ventrolateral PFC or in SFC. These results suggest that the delay-related function of SFC is limited to the maintenance of spatial information, and that this region does not support the nonmnemonic executive control functions supported by dorsolateral PFC. These results also indicate that the perferential recruitment of dorsolateral PFC for the manipulation of information held in working memory applies to tasks employing spatial stimuli, as well as to tasks employing verbal stimuli (D'Esposito et al., 1999: Petrides et al., 1993; Postle et al., 1999).

Supplemental Information

Language: English
fMRIDC Comments: Dataset Size: 808K Available on 1 CD
Country: USA
Magnetic Field Strength: 1.5T
Scanner Manufacturer: GE Signa
Analysis Software: Custom
Cognitive Domain: Working Memory (Spatial)
Subjects: 5
Age Range: 18-26
Functional Runs: 5
Has anatomical data
Has raw image data
Has high-res images
Has preprocessed image data

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