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Two common psychophysical measures of surround suppression reflect independent neuronal mechanisms.

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Yazdani, Partow and Serrano-Pedraza, Ignacio and Whittaker, Roger G and Trevelyan, Andrew and Read, Jenny C A (2015) Two common psychophysical measures of surround suppression reflect independent neuronal mechanisms. Journal of vision, 15 (13). p. 21. ISSN 1534-7362

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Official URL: http://dx.doi.org/10.1167/15.13.21



Abstract

Psychophysical surround suppression is believed to reflect inhibitory neuronal mechanisms in visual cortex. In recent years, two psychophysical measures of surround suppression have been much studied: (i) duration thresholds on a motion-discrimination task (which are worse for larger than for smaller stimuli) and (ii) contrast thresholds on a contrast-detection task (which are worse when grating stimuli are surrounded by a stimulus of the same orientation than when they are presented in isolation or surrounded by a stimulus of orthogonal orientation). Changes in both metrics have been linked to several different human conditions, including aging, differences in intelligence, and clinical disorders such as schizophrenia, depression, and autism. However, the exact nature of the neuronal correlate underlying these phenomena remains unclear. Here, we use an individual-differences approach to test the hypothesis that both measures reflect the same property of the visual system, e.g., the strength of GABA-ergic inhibition across visual cortex. Under this hypothesis we would expect the two measures to be significantly positively correlated across individuals. In fact, they are not significantly correlated. In addition, we replicate the previously reported correlation between age and motion-discrimination surround suppression, but find no correlation between age and contrast-detection surround suppression. We conclude that the two forms of psychophysical surround suppression arise independently from different cortical mechanisms.


Item Type:Article
Uncontrolled Keywords:Visual surround suppression, Psychophysics, Motion perception, Vision, GABA
Subjects:Medical sciences > Psychology > Experimental psychology
Medical sciences > Psychology > Perception
Medical sciences > Optics > Visual perception
ID Code:36267
Deposited On:12 Apr 2016 11:31
Last Modified:12 Apr 2016 11:31

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