Please use this identifier to cite or link to this item: http://hdl.handle.net/1893/20535
Appears in Collections:Psychology Journal Articles
Peer Review Status: Refereed
Title: The spatial feature underlying the shape-frequency and shape-amplitude after-effects
Authors: Gheorghiu, Elena
Kingdom, Frederick A A
Contact Email: elena.gheorghiu@stir.ac.uk
Keywords: Contour-shape
Adaptation
Shape-frequency after-effect
Shape-amplitude after-effect
Curvature
Tilt after-effect
Issue Date: Mar-2007
Publisher: Elsevier
Citation: Gheorghiu E & Kingdom FAA (2007) The spatial feature underlying the shape-frequency and shape-amplitude after-effects, Vision Research, 47 (6), pp. 834-844.
Abstract: The shape-frequency and shape-amplitude after-effects, or SFAE and SAAE, refer respectively to the shifts observed in the perceived shape-frequency and shape-amplitude of a sinusoidal test contour following adaptation to a similar-shaped contour. As with other shape after-effects the shifts are in a direction away from that of the adapting stimulus. Using a variety of procedures we tested whether the spatial feature that was adapted in the SFAE and SAAE was (a) local orientation, (b) average unsigned curvature, (c) periodicity/density, (d) shape-amplitude and (e) local curvature. Our results suggest that the last of these, local curvature, underlies both the SFAE and SAAE. The evidence in favour of local curvature was that the after-effect reached its maximum value when just half-a-cycle of the test contour, in +/-cosine phase, was present. We suggest that the SFAE and SAAE are mediated by intermediate-level mechanisms that encode the shapes of contour fragments with constant sign of curvature. Given the neurophysiological evidence that neurons in area V4 encode parts of shapes with constant sign of curvature, we suggest V4 is the likely neural substrate for both the SFAE and SAAE.
Type: Journal Article
URI: http://hdl.handle.net/1893/20535
DOI Link: http://dx.doi.org/10.1016/j.visres.2006.11.023
Rights: The publisher does not allow this work to be made publicly available in this Repository. Please use the Request a Copy feature at the foot of the Repository record to request a copy directly from the author. You can only request a copy if you wish to use this work for your own research or private study.
Affiliation: Psychology
McGill University

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