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Abstract:
Abstract: People can fail to detect an obvious change in an
image if the change occurs during a brief blank interval ("change
blindness", Rensink et al., 1997). Here we used event-related fMRI
to investigate change blindness. Subjects were asked to detect
whether one of two images changed or not, while performing a
central letter detection task. The difficulty of the letter task
was adjusted so that the rate of detected and undetected changes
was approximately equal. We used both faces and outdoor places. As
expected, the faces activated right fusiform gyrus (ffa) and the
places activated parahippocampal cortex (ppa; Epstein &
Kanwisher, 1998). Importantly, activity in ffa was greater for
detected versus undetected face changes, and activity in ppa was
greater for detected versus undetected place changes. Moreover,
regardless of whether the change concerned a face or a place,
change detection produced significantly greater activity in right
lateral prefrontal cortex (BA 46) and bilateral superior parietal
cortex. Interestingly, when subjects were unaware of the change,
face changes produced activity in early visual cortex but not in
ffa or the dorsal stream, suggesting that object specific areas
(e.g. ffa for faces) and parietal cortex are particularly important
for conscious awareness of change.
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