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Functional specialization and dynamic resource allocation in visual cortex

✍ Scribed by Gijs Plomp; Cees van Leeuwen; Andreas A. Ioannides


Book ID
102846140
Publisher
John Wiley and Sons
Year
2009
Tongue
English
Weight
807 KB
Volume
31
Category
Article
ISSN
1065-9471

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✦ Synopsis


Abstract

We studied the spatiotemporal characteristics of cortical activity in early visual areas and the fusiform gyri (FG) by means of magnetoencephalography (MEG). Subjects performed a visual classification task, in which letters and visually similar pseudoletters were presented in different surrounds and under different task demands. The stimuli appeared in a cued half of the visual field (VF). We observed prestimulus effects on amplitudes in V1 and Cuneus relating to VF and task demands, suggesting a combination of active anticipation and specialized routing of activity in visual processing. Amplitudes in the right FG between 150 and 350 ms after stimulus onset reflected task demands, while those in the left FG between 300 and 400 ms showed selectivity for graphemes. The contrasting stimulus‐evoked effects in the right and left FG show that the former area is sensitive to task demands irrespective of stimulus content, whereas the left FG is sensitive to stimulus content irrespectively of task demand. Hum Brain Mapp, 2010. Β© 2009 Wiley‐Liss, Inc.


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