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Abstract:
Visuospatial attention allows observers to focus awareness on
one or several pieces of information in the visual world. Recent
evidence suggests that a network of brain regions including
superior frontal, inferior parietal, and superior temporal cortices
is involved in the top-down control of visuospatial attention. The
goal of this study was to determine whether this network mediates
attentional control in different visual frames of reference (FORs),
or whether partially separable neural systems underlie attentional
orienting in each. Participants were cued to locations defined
within viewer- or object-centered FORs and made form
discriminations on targets subsequently presented at those
locations. Cortical responses to attention-directing cues were
recorded with event-related fMRI at 1.5T. Consistent with previous
work, a number of brain regions were selectively activated by
attention-directing cues including superior frontal, inferior
parietal, and superior temporal cortices. Critically, this network
was differentially engaged when attention was grounded in different
FORs. Specifically, superior temporal regions were more active when
spatial attention was deployed within an object-centered FOR,
whereas superior frontal regions were more active when spatial
attention was deployed within a viewer-centered FOR. Inferior
parietal regions were equally responsive to attention-directing
cues in both FORs. These results suggest that attentional orienting
in different FORs is mediated by an overlapping network of brain
regions, but that this network is differentially engaged when
attention is deployed in different reference frames.
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