کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10466609 925772 2009 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The role of the posterior parietal cortex in drawing by copying
موضوعات مرتبط
علوم زیستی و بیوفناوری علم عصب شناسی علوم اعصاب رفتاری
پیش نمایش صفحه اول مقاله
The role of the posterior parietal cortex in drawing by copying
چکیده انگلیسی
Impaired ability to draw visually presented figures by copying represents one major manifestation of constructional apraxia (CA). Previous clinical studies have indicated that CA is caused by lesions in the posterior parietal cortex (PPC), but the functional roles of the PPC remain unclear. A spared ability to trace with an impaired ability to copy indicates that deficits lie not in low-level visuomotor processing, but rather in a coordinate transformation involving production of an egocentric representation of model trajectory in the drawing space, which is spatially separated from the model space. To test the hypothesis that the PPC plays a role in coordinate transformation, we compared brain activities for drawing by copying and tracing using functional magnetic resonance imaging (fMRI). Healthy participants traced over the visually presented model or copied the model on a separate space. To avoid potential confounders of differences in behavioral performances as well as eye movements, a memory-guided condition was introduced, resulting in four drawing conditions; tracing over or copying a model at different locations (tracing and copying), with or without an on-screen model (visual and memory guidance). As hypothesized, the intraparietal sulcus (IPS) bilaterally in the PPC showed significantly greater activations in copying than in tracing, under both visual and memory guidance, with a distinct activation pattern involving the premotor and mesial motor regions. This study indicates a role of the PPC in coordinate transformation for drawing by copying, which may be important for the copying deficit observed in CA.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Neuropsychologia - Volume 47, Issue 4, March 2009, Pages 1013-1022
نویسندگان
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