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Contour Integration over Time: Psychophysical and fMRI Evidence.

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Kuai, S-G 
Li, W 
Yu, C 

Abstract

The brain integrates discrete but collinear stimuli to perceive global contours. Previous contour integration (CI) studies mainly focus on integration over space, and CI is attributed to either V1 long-range connections or contour processing in high-visual areas that top-down modulate V1 responses. Here, we show that CI also occurs over time in a design that minimizes the roles of V1 long-range interactions. We use tilted contours embedded in random orientation noise and moving horizontally behind a fixed vertical slit. Individual contour elements traveling up/down within the slit would be encoded over time by parallel, rather than aligned, V1 neurons. However, we find robust contour detection even when the slit permits only one viewable contour element. Similar to CI over space, CI over time also obeys the rule of collinearity. fMRI evidence shows that while CI over space engages visual areas as early as V1, CI over time mainly engages higher dorsal and ventral visual areas involved in shape processing, as well as posterior parietal regions involved in visual memory that can represent the orientation of temporally integrated contours. These results suggest at least partially dissociable mechanisms for implementing the Gestalt rule of continuity in CI over space and time.

Description

Keywords

Gestalt principles, contour integration, fMRI, good continuity, psychophysics

Journal Title

Cerebral Cortex

Conference Name

Journal ISSN

1047-3211
1460-2199

Volume Title

27

Publisher

Oxford University Press (OUP)
Sponsorship
European Commission (290011)
European Community’s Seventh Framework Programme (FP7/2007-2013) (Grant ID: 255577), Biotechnology and Biological Sciences Research Council (Grant IDs: D52199X , E027436), National Natural Science Foundation of China (Grant IDs: 31230030, 31571160, 91432102)