Summers, Robert J, Baker, Daniel Hart orcid.org/0000-0002-0161-443X and Meese, Tim S (2015) Area summation of first- and second-order modulations of luminance. Journal of Vision. 12. pp. 1-13. ISSN 1534-7362
Abstract
To extend our understanding of the early visual hierarchy, we investigated the long-range integration of first- and second-order signals in spatial vision. In our first experiment we performed a conventional area summation experiment where we varied the diameter of (a) luminance-modulated (LM) noise and (b) contrast-modulated (CM) noise. Results from the LM condition replicated previous findings with sine-wave gratings in the absence of noise, consistent with long-range integration of signal contrast over space. For CM, the summation function was much shallower than for LM suggesting, at first glance, that the signal integration process was spatially less extensive than for LM. However, an alternative possibility was that the high spatial frequency noise carrier for the CM signal was attenuated by peripheral retina (or cortex), thereby impeding our ability to observe area summation of CM in the conventional way. To test this, we developed the “Swiss cheese” stimulus of Meese and Summers (2007) in which signal area can be varied without changing the stimulus diameter, providing some protection against inhomogeneity of the retinal field. Using this technique and a two-component subthreshold summation paradigm we found that (a) CM is spatially integrated over at least five stimulus cycles (possibly more), (b) spatial integration follows square-law signal transduction for both LM and CM and (c) the summing device integrates over spatially-interdigitated LM and CM signals when they are co-oriented, but not when cross-oriented. The spatial pooling mechanism that we have identified would be a good candidate component for a module involved in representing visual textures, including their spatial extent.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2015, ARVO. |
Keywords: | Area summation,Second order,Cue combination,Computational modeling |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Psychology (York) |
Depositing User: | Pure (York) |
Date Deposited: | 10 Aug 2016 13:19 |
Last Modified: | 16 Oct 2024 12:29 |
Published Version: | https://doi.org/10.1167/15.1.12 |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.1167/15.1.12 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:103310 |