Neural timing of visual implicit categorization.

Details

Serval ID
serval:BIB_EF15428262A6
Type
Article: article from journal or magazin.
Collection
Publications
Title
Neural timing of visual implicit categorization.
Journal
Brain Research. Cognitive Brain Research
Author(s)
Pernet C., Basan S., Doyon B., Cardebat D., Démonet J.F., Celsis P.
ISSN
0926-6410 (Print)
ISSN-L
0926-6410
Publication state
Published
Issued date
2003
Peer-reviewed
Oui
Volume
17
Number
2
Pages
327-338
Language
english
Notes
Publication types: Journal ArticlePublication Status: ppublish. PDF type: Research report
Abstract
Most of the neuroimaging studies that have shown visual category-specific activations or categorization effects have been based on a subtractive approach. In the present study, we investigated, by means of EEG, not only the net result of the categorization but also the dynamics of the process. Subjects had to perform a target detection task throughout an image set of distractors belonging to six categories: letters, geometrical figures, faces, tools, structured textures and Asiatic characters. Multivariate analyses were performed on the responses to the non-target stimuli according to their category. Categorical neural responses were only obtained on P2 latencies and N2 amplitudes. This result suggests that there are no differences in the first stage of the implicit categorization of the distractors (visual analysis and proximal stimulus representation elaboration from 100 to 220 ms) and that differences appear between 220 and 280 ms (matching to structural representations). Over-learned stimuli (e.g. letters) elicited the shortest P2 latency, contrasting with unknown categories (e.g. Asiatic characters) that revealed the longest P2 latencies and flattened N2 waves. Categorical differences indicate that the more a subject knows about an object, the less cognitive resources are used. In conclusion, our results suggest that a reduction in neural activity could reflect an improved accuracy in cognitive and cortical processing.
Keywords
Adult, Analysis of Variance, Evoked Potentials, Visual/physiology, Female, Humans, Male, Multivariate Analysis, Nerve Net/physiology, Pattern Recognition, Visual/classification, Pattern Recognition, Visual/physiology, Photic Stimulation/methods, Reaction Time/physiology
Pubmed
Web of science
Create date
24/03/2013 19:36
Last modification date
03/03/2018 22:34
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