The spatiotemporal dynamics of illusory contour processing: combined high-density electrical mapping, source analysis, and functional magnetic resonance imaging
Details
Serval ID
serval:BIB_2C596046876C
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
The spatiotemporal dynamics of illusory contour processing: combined high-density electrical mapping, source analysis, and functional magnetic resonance imaging
Journal
Journal of Neuroscience
ISSN
1529-2401
Publication state
Published
Issued date
06/2002
Peer-reviewed
Oui
Volume
22
Number
12
Pages
5055-73
Notes
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S. --- Old month value: Jun 15
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S. --- Old month value: Jun 15
Abstract
Because environmental information is often suboptimal, visual perception must frequently rely on the brain's reconstruction of contours absent from retinal images. Illusory contour (IC) stimuli have been used to investigate these "filling-in" processes. Intracranial recordings and neuroimaging studies show IC sensitivity in lower-tier area V2, and to a lesser extent V1. Some interpret these data as evidence for feedforward processing of IC stimuli, beginning at lower-tier visual areas. On the basis of lesion, visual evoked potentials (VEP), and neuroimaging evidence, others contend that IC sensitivity is a later, higher-order process. Whether IC sensitivity seen in lower-tier areas indexes feedforward or feedback processing remains unresolved. In a series of experiments, we addressed the spatiotemporal dynamics of IC processing. Centrally presented IC stimuli resulted in early VEP modulation (88-100 msec) over lateral-occipital (LOC) scalp--the IC effect. The IC effect followed visual response onset by 40 msec. Scalp current density topographic mapping, source analysis, and functional magnetic resonance imaging results all localized the IC effect to bilateral LOC areas. We propose that IC sensitivity described in V2 and V1 may reflect predominantly feedback modulation from higher-tier LOC areas, where IC sensitivity first occurs. Two additional observations further support this proposal. The latency of the IC effect shifted dramatically later (approximately 120 msec) when stimuli were laterally presented, indicating that retinotopic position alters IC processing. Immediately preceding the IC effect, the VEP modulated with inducer eccentricity--the configuration effect. We interpret this to represent contributions from global stimulus parameters to scene analysis. In contrast to the IC effect, the topography of the configuration effect was restricted to central parieto-occipital scalp.
Keywords
Adult
Brain/anatomy & histology
Brain Mapping/*methods
Evoked Potentials, Visual
Feedback
Female
*Form Perception
Humans
Imaging, Three-Dimensional/methods
Kinetics
Magnetic Resonance Imaging/*methods
Male
Middle Aged
Occipital Lobe/*physiology
Optical Illusions
Pubmed
Web of science
Create date
21/01/2008 10:23
Last modification date
20/08/2019 13:11