Comparison of early cortical networks in efficient and inefficient visual search: an event-related potential study.

Details

Serval ID
serval:BIB_4F0C86B3ED66
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Comparison of early cortical networks in efficient and inefficient visual search: an event-related potential study.
Journal
Journal of cognitive neuroscience
Author(s)
Leonards U., Palix J., Michel C., Ibanez V.
ISSN
0898-929X
Publication state
Published
Issued date
2003
Volume
15
Number
7
Pages
1039-51
Language
english
Notes
Publication types: Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't - Publication Status: ppublish
Abstract
Functional magnetic resonance imaging studies have indicated that efficient feature search (FS) and inefficient conjunction search (CS) activate partially distinct frontoparietal cortical networks. However, it remains a matter of debate whether the differences in these networks reflect differences in the early processing during FS and CS. In addition, the relationship between the differences in the networks and spatial shifts of attention also remains unknown. We examined these issues by applying a spatio-temporal analysis method to high-resolution visual event-related potentials (ERPs) and investigated how spatio-temporal activation patterns differ for FS and CS tasks. Within the first 450 msec after stimulus onset, scalp potential distributions (ERP maps) revealed 7 different electric field configurations for each search task. Configuration changes occurred simultaneously in the two tasks, suggesting that contributing processes were not significantly delayed in one task compared to the other. Despite this high spatial and temporal correlation, two ERP maps (120-190 and 250-300 msec) differed between the FS and CS. Lateralized distributions were observed only in the ERP map at 250-300 msec for the FS. This distribution corresponds to that previously described as the N2pc component (a negativity in the time range of the N2 complex over posterior electrodes of the hemisphere contralateral to the target hemifield), which has been associated with the focusing of attention onto potential target items in the search display. Thus, our results indicate that the cortical networks involved in feature and conjunction searching partially differ as early as 120 msec after stimulus onset and that the differences between the networks employed during the early stages of FS and CS are not necessarily caused by spatial attention shifts.
Keywords
Adult, Analysis of Variance, Cerebral Cortex, Evoked Potentials, Female, Humans, Male, Nerve Net, Photic Stimulation, Statistics, Nonparametric, Vision, Ocular
Create date
19/11/2007 10:26
Last modification date
20/08/2019 14:04
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