Early differential sensitivity of evoked-potentials to local and global shape during the perception of three-dimensional objects

Leek, EC, Roberts, M, Oliver, ZJ, Cristino, F ORCID: https://orcid.org/0000-0002-9366-293X and Pegna, AJ, 2016. Early differential sensitivity of evoked-potentials to local and global shape during the perception of three-dimensional objects. Neuropsychologia, 89, pp. 495-509. ISSN 0028-3932

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Abstract

Here we investigated the time course underlying differential processing of local and global shape information during the perception of complex three-dimensional (3D) objects. Observers made shape matching judgments about pairs of sequentially presented multipart novel objects. Event-related potentials (ERPs) were used to measure perceptual sensitivity to 3D shape differences in terms of local part structure and global shape configuration - based on predictions derived from hierarchical structural description models of object recognition. There were three types of different object trials in which stimulus pairs (1) shared local parts but differed in global shape configuration; (2) contained different local parts but shared global configuration or (3) shared neither local parts nor global configuration. Analyses of the ERP data showed differential amplitude modulation as a function of shape similarity as early as the N1 component between 146-215 ms post-stimulus onset. These negative amplitude deflections were more similar between objects sharing global shape configuration than local part structure. Differentiation among all stimulus types was reflected in N2 amplitude modulations between 276–330 ms. sLORETA inverse solutions showed stronger involvement of left occipitotemporal areas during the N1 for object discrimination weighted towards local part structure. The results suggest that the perception of 3D object shape involves parallel processing of information at local and global scales. This processing is characterised by relatively slow derivation of ‘fine-grained’ local shape structure, and fast derivation of ‘coarse-grained’ global shape configuration. We propose that the rapid early derivation of global shape attributes underlies the observed patterns of N1 amplitude modulations.

Item Type:	Journal article
Publication Title:	Neuropsychologia
Creators:	Leek, E.C., Roberts, M., Oliver, Z.J., Cristino, F. and Pegna, A.J.
Publisher:	Pergamon Press
Date:	August 2016
Volume:	89
ISSN:	0028-3932
Identifiers:	Number Type 10.1016/j.neuropsychologia.2016.07.006 DOI S0028393216302445 Publisher Item Identifier
Rights:	© 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.
Divisions:	Schools > School of Social Sciences
Record created by:	Jonathan Gallacher
Date Added:	16 Oct 2017 09:47
Last Modified:	18 Oct 2017 14:32
URI:	https://irep.ntu.ac.uk/id/eprint/31820

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