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Abstract:
Abstract: A variety of lines of evidence support the claim
that stimuli are automatically marked for location in an egocentric
frame. We tested the hypothesis that even cognitive operations such
as language, which have no explicit spatial dimension, are
influenced by spatial factors. In Exp. 1, 52 subjects with cerebral
lesions (34 with parietal involvement [23 LH and 11 RH], 18 without
[11 LH and 7 RH]) performed language tasks on two occasions, once
with stimuli presented 30° to the right and once 30° to the
left of body midline. Tasks included picture naming, oral reading,
synonymy judgment and sentence comprehension. As a group, parietal
but not non-parietal subjects showed significant hemispatial bias,
performing less well in the contralesional as compared to the
ipsilesional hemispace. Nine subjects, all with parietal lesions,
performed consistently better in the ipsilesional hemispace. In
Exp. 2, subjects with hemispatial bias in language (n=6) and those
without (n=13) performed tasks assessing visual and auditory
spatial processing. There was a significant association between
impaired performance on tasks assessing spatial systems and
hemispatial bias in language. These findings are consistent with
the hypothesis that not only motor and sensory but even cognitive
operations such as language which have no explicit spatial
dimension are maintained in registration with spatial systems.
Disruption of this binding, which appears to critically involve the
parietal lobe, is associated with impaired performance on language
tasks.
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