Setting boundaries: brain dynamics of modal and amodal illusory shape completion in humans.

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Serval ID
serval:BIB_07330509DA7A
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Setting boundaries: brain dynamics of modal and amodal illusory shape completion in humans.
Journal
Journal of Neuroscience
Author(s)
Murray M.M., Foxe D.M., Javitt D.C., Foxe J.J.
ISSN
1529-2401[electronic]
Publication state
Published
Issued date
2004
Volume
24
Number
31
Pages
6898-68903
Language
english
Abstract
Normal visual perception requires differentiating foreground from background objects. Differences in physical attributes sometimes determine this relationship. Often such differences must instead be inferred, as when two objects or their parts have the same luminance. Modal completion refers to such perceptual "filling-in" of object borders that are accompanied by concurrent brightness enhancement, in turn termed illusory contours (ICs). Amodal completion is filling-in without concurrent brightness enhancement. Presently there are controversies regarding whether both completion processes use a common neural mechanism and whether perceptual filling-in is a bottom-up, feedforward process initiating at the lowest levels of the cortical visual pathway or commences at higher-tier regions. We previously examined modal completion (Murray et al., 2002) and provided evidence that the earliest modal IC sensitivity occurs within higher-tier object recognition areas of the lateral occipital complex (LOC). We further proposed that previous observations of IC sensitivity in lower-tier regions likely reflect feedback modulation from the LOC. The present study tested these proposals, examining the commonality between modal and amodal completion mechanisms with high-density electrical mapping, spatiotemporal topographic analyses, and the local autoregressive average distributed linear inverse source estimation. A common initial mechanism for both types of completion processes (140 msec) that manifested as a modulation in response strength within higher-tier visual areas, including the LOC and parietal structures, is demonstrated, whereas differential mechanisms were evident only at a subsequent time period (240 msec), with amodal completion relying on continued strong responses in these structures.
Keywords
Adult, Electroencephalography, Evoked Potentials, Visual, Female, Humans, Illusions, Male, Visual Pathways
Pubmed
Web of science
Open Access
Yes
Create date
21/01/2008 10:23
Last modification date
20/08/2019 12:29
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