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Suppression pathways saturate with contrast for parallel surrounds but not for superimposed cross-orientated masks

Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.14/126172

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Title: Suppression pathways saturate with contrast for parallel surrounds but not for superimposed cross-orientated masks
Related: Vision research, Vol. 49, Issue 24 (2009), p.2927-2935
DOI: 10.1016/j.visres.2009.09.006
Publisher: Elsevier
Date: 2009
FoR/RFCD Code(s): 110900 Neurosciences 170200 Cognitive Sciences 111300 Ophthalmology and Optometry
Author/Creator: Meese, Tim S
Author/Creator: Challinor, Kirsten L
Author/Creator: Summers, Robert J
Author/Creator: Baker, Daniel H
Description: Contrast masking from parallel grating surrounds (doughnuts) and superimposed orthogonal masks have different characteristics. However, it is not known whether the saturation of the underlying suppression that has been found for parallel doughnut masks depends on (i) relative mask and target orientation, (ii) stimulus eccentricity or (iii) surround suppression. We measured contrast-masking functions for target patches of grating in the fovea and in the periphery for cross-oriented superimposed and doughnut masks and parallel doughnut masks. When suppression was evident, the factor that determined whether it accelerated or saturated was whether the mask stimulus was crossed or parallel. There are at least two interpretations of the asymptotic behaviour of the parallel surround mask. (1) Suppression arises from pathways that saturate with (mask) contrast. (2) The target is processed by a mechanism that is subject to surround suppression at low target contrasts, but a less sensitive mechanism that is immune from surround suppression ‘breaks through’ at higher target contrasts. If the mask can be made less potent, then masking functions should shift downwards, and sideways for the two accounts, respectively. We manipulated the potency of the mask by varying the size of the hole in a parallel doughnut mask. The results provided strong evidence for the first account but not the second. On the view that response compression becomes more severe progressing up the visual pathway, our results suggest that superimposed cross-orientation suppression precedes orientation tuned surround suppression. These results also reveal a previously unrecognized similarity between surround suppression and crowding (Pelli, Palomares, & Majaj, 2004).
Description: 9 page(s)
Subject Keyword: 110900 Neurosciences
Subject Keyword: 170200 Cognitive Sciences
Subject Keyword: 111300 Ophthalmology and Optometry
Subject Keyword: human vision
Subject Keyword: contrast gain control
Subject Keyword: psychophysics
Subject Keyword: surround suppression
Subject Keyword: crowding
Subject Keyword: XOM
Subject Keyword: XOS
Subject Keyword: detection
Resource Type: journal article
Organisation: Macquarie University. Dept. of Psychology

Identifier: http://hdl.handle.net/1959.14/126172
Identifier: ISSN:0042-6989
Identifier: mq-rm-2010005136
Language: eng
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