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Abstract:
Abstract: The Parahippocampal Place Area (PPA; Epstein &
Kanwisher, 1998) is a region within parahippocampal cortex that
responds selectively to visual stimuli that convey information
about the layout of local space. Here we test whether the PPA is
more involved in the on-line perceptual analysis of scene geometry
or the encoding of this information into memory. We describe two
patients who suffered damage to the PPA after vascular incidents.
Both subsequently exhibited memory problems for topographical
materials and were unable to navigate unassisted in unfamiliar
environments. Performance on a continuous n-back visual memory test
was significantly lower for novel scene-like stimuli than for novel
object-like stimuli. In contrast, performance was normal on a
famous landmark recognition task and on two perceptual tasks that
required on-line analysis of scene geometry. Both patients were
able to produce accurate maps of premorbidly-learned places but
were unable to produce accurate maps of new places. These results
indicate that the PPA (1) is selectively involved in processing
information about the geometry of local space, and (2) plays a more
critical role in the encoding of place information into memory than
in the initial perceptual processing, recognition, or recall of
this information.
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