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Abstract:
Abstract: Prior studies have demonstrated differential
activity between novel and familiar items both in visual cortical
areas and in the hippocampal formation. Other work has tied
hippocampal activity to memory for relations among items. Using
rapid-presentation event-related fMRI (whole-brain fMRI, 1.5 Tesla
scanner, asymmetric spin-echo, TR = 2.68 sec), we extend these
investigations in 12 subjects imaged while intentionally memorizing
pairs of faces. Prior to imaging, subjects studied a series of face
pairs four times each. Then during scanning, subjects memorized
face pairs that were either NOVEL (two faces never seen before),
REPEATED (a previously studied face pair), or RE-PAIRED (faces
taken from different previously studied pairs). Activity in early
visual cortex did not differ across these three types of face
pairs. Activity in the right fusiform gyrus was greatest during
memorization of NOVEL face pairs and did not differ between
REPEATED and RE-PAIRED faces, suggesting this region was sensitive
to the relative novelty of the individual faces, as is seen in
studies of repetition priming. By contrast, activity in the right
hippocampal formation was greatest during memorization of RE-PAIRED
faces, suggesting this region was most sensitive to and presumably
involved in memory for the relations between faces.29A
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