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Abstract:
Abstract: Recent research indicated an involvement of the
prefrontal cortex in the processing of temporal information. The
aim of the present study was to test the hypothesis that
impairments of temporal duration processing after frontal lobe
lesions reflect deficits in executive monitoring functions rather
than a domain-specific deficit in the maintenance of duration
information in working memory. Patients with frontodorsal lesions,
clinical controls with post-central lesions, and healthy controls
performed recognition and classification tasks, which should allow
for testing maintenance and monitoring functions, respectively.
Recognition tests demanded subjects to indicate whether a
repeatedly presented stimulus was the same or different with
respect to duration or location. In classification tasks subjects
had to indicate whether a defined reference stimulus out of two
successive, random stimuli was longer in presentation duration or
higher in position than the comparison cue. Results showed mild
non-selective impairments of the frontal patients on both the
temporal and the spatial recognition tasks, but a marked selective
degradation on temporal classification while performance on spatial
classification was unimpaired. This suggests that maintenance of
duration information in working memory after frontal lesions is
basically preserved but that, depending on executive task
characteristics, there is a specific deficit in the strategic
organization of this type of information.
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