A two-stage model of orientation integration for Battenberg-modulated micropatterns

Abstract

The visual system pools information from local samples to calculate textural properties. We used a novel stimulus to investigate how signals are combined to improve estimates of global orientation. Stimuli were 29 × 29 element arrays of 4 c/deg log Gabors, spaced 1° apart. A proportion of these elements had a coherent orientation (horizontal/vertical) with the remainder assigned random orientations. The observer's task was to identify the global orientation. The spatial configuration of the signal was modulated by a checkerboard pattern of square checks containing potential signal elements. The other locations contained either randomly oriented elements (''noise check'') or were blank (''blank check''). The distribution of signal elements was manipulated by varying the size and location of the checks within a fixed-diameter stimulus. An ideal detector would only pool responses from potential signal elements. Humans did this for medium check sizes and for large check sizes when a signal was presented in the fovea. For small check sizes, however, the pooling occurred indiscriminately over relevant and irrelevant locations. For these check sizes, thresholds for the noise check and blank check conditions were similar, suggesting that the limiting noise is not induced by the response to the noise elements. The results are described by a model that filters the stimulus at the potential target orientations and then combines the signals over space in two stages. The first is a mandatory integration of local signals over a fixed area, limited by internal noise at each location. The second is a taskdependent combination of the outputs from the first stage.

Publication DOI: https://doi.org/10.1167/14.1.30
Divisions: College of Health & Life Sciences > School of Psychology
College of Health & Life Sciences > School of Optometry
College of Health & Life Sciences > Clinical and Systems Neuroscience
College of Health & Life Sciences
College of Health & Life Sciences > Vision, Hearing and Language
College of Health & Life Sciences > Centre for Vision and Hearing Research
Additional Information: © 2014 ARVO Funding: NSERCouncil (Canada) (#46528-11); EPSRC (UK) (#EP/H000038/1).
Uncontrolled Keywords: computational modeling,integration,orientation,summation,texture perception,Ophthalmology,Sensory Systems
Full Text Link:
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
http://jov.arvo ... ticleid=2193947 (Publisher URL)
PURE Output Type: Article
Published Date: 2014-01-30
Authors: Baldwin, Alex S.
Husk, Jesse S.
Meese, Tim S. (ORCID Profile 0000-0003-3744-4679)
Hess, Robert F.

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