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Abstract:
Abstract: Text processing requires inferences to bridge gaps
between successive sentences. In neuropsychological and brain
imaging studies, these coherence building processes have been
ascribed to the right hemisphere. In this study, we use an
event-related, whole head fMRI methodology to describe in more
detail the brain regions involved in inference processes. We
scanned 12 participants while they read 120 sentence pairs and
judged their coherence. Two factors were crossed: Coherence - the
two sentences were either pragmatically coherent or incoherent -,
and Cohesion - the second sentence either contained a lexical item
indicating a relationship, or it did not. Cohesion is facilitative
in coherent trials but misleading in incoherent trials. Compared to
a control condition (letter size judgment), all language conditions
yielded activation in left fronto-opercular and lateral temporal
regions. In addition, we found left-lateralized activation in the
fronto-median wall, the precuneus and the retrosplenial cortex.
Contrasting coherent with incoherent trials, there was considerable
activation in left fronto-median areas, as well as in the posterior
hippocampal formation bilaterally. Incoherent trials, as compared
to coherent trials, elicited bilateral activation along the banks
of the inferior frontal sulcus. Cohesion had an impact on the
lateralization of the latter activation. These results are
consistent with previous imaging studies on text processes, but
they do not confirm a special role of the right hemisphere for
inference processes.
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