208 pp. per issue
8 1/2 x 11, illustrated
2014 Impact factor:

Journal of Cognitive Neuroscience

November 1999, Vol. 11, No. 6, Pages 585-597
(doi: 10.1162/089892999563652)
© 1999 Massachusetts Institute of Technology
“What”—Then—“Where” in Visual Working Memory: An Event-Related fMRI Study
Article PDF (1.04 MB)

Behavioral studies indicate that spatial and object working memory are computed by dissociable subsystems. We investigated the neural bases of this dissociation with a whole-brain fMRI design and analysis technique that permitted direct assessment of delay-period activity, uncontaminated by other components of the trial. The task employed a “what”-then-“where” design, with an object and a spatial delay period incorporated in each trial; within-trial order of delay conditions was balanced across each scan. Our experiment failed to find evidence, at the single-subject level and at the group level, for anatomical segregation of spatial and object working memory function in the frontal cortex. Delay-period activity in the caudate nucleus revealed a sensitivity to position in the trial in the spatial, but not the object, condition. In posterior regions, spatial delay-period activity was associated with preferential recruitment of extrastriate areas falling within Brodmann's area 19 and, less reliably, the superior parietal lobule. Object-specific delay-period activity was found predominantly in ventral regions of the posterior cortex and demonstrated more topographic variability across subjects than did spatial working memory activity.