Motion direction tuning in centre-surround suppression of contrast. (February 2021)

• Record Type: Journal Article
• Authors: Phillips, Daisy J.; McDougall, Thomas J.; Dickinson, J. Edwin; Badcock, David R.
• Is Part Of: Vision research. Volume 179(2021)
• Page Start: 85
• Page End: 93
• Publication Date: 2021-02
• Subjects: Surround suppression -- Centre-surround suppression -- Motion processing -- Psychophysics -- Contrast suppression; Vision -- Periodicals; 573.88
• DOI: 10.1016/j.visres.2020.11.001
• Languages: English
• ISSNs: 0042-6989

Abstract

Highlights: Relative motion direction mediates centre-surround suppression of contrast. Contrast suppression has components tuned and un-tuned for motion direction. The tuned component has a Gaussian suppression profile with a SD of 28°. Centre-surround suppression of contrast for motion is analogous to that for form. Contrast suppression can be modelled by lateral inhibition in a bank of channels. Abstract: The perceived contrast of a central stimulus is reduced in the presence of a high contrast surround. A number of stimulus features influence the amount of suppression. A two-mechanism model has been proposed for stationary patterns involving a narrowly-tuned process, requiring very similar stimuli in the centre and surround, and a weaker, untuned or very broadly tuned process unselective for stimulus features. This study examines whether a similar model applies to the motion pathway in human participants by varying the orientation and direction of motion of the surround relative to the centre. Four experienced observers completed a two-interval forced-choice contrast matching task. The stimuli were drifting sinusoidal grating patterns with high contrast surrounds (95%) differing in direction of motion and orientation relative to the centre grating. All surround conditions produced suppression but a common orientation and direction of motion produced significantly more suppression than either opposite direction of motion conditions or orthogonal direction conditions. The tuning for motion direction differences was assessed for same and opposite directions of motion. These findings support the extension of the two-mechanism model of contrast suppression to motion direction.