Collinear facilitation and suppression at the periphery

Abstract

Collinear facilitation is a common phenomenon in the fovea, but it has been recently challenged at the human periphery. Since physiological studies show that facilitation is found at the periphery but only from outside the receptive field, our hypothesis was that facilitation at the periphery exists but from larger target-flanker separations than the fovea. Here, we applied a recent paradigm (Polat & Sagi, 2007) to probe facilitation at the periphery. We used a Yes/No detection task by measuring the false-positive reports (false-alarm, pfa) and hit-rate (phit) for a low-contrast Gabor target (between two flankers) that appeared randomly at the fovea or at the periphery (2° or 4°) to the right or left side. We used different target-flanker separations and orientations at the fovea and at the periphery. Importantly, we found that phit is affected by the target-flanker separations and orientations. Short distances show a suppression effect, but the range of suppression increases with increasing eccentricity. A facilitation effect was found for collinear configuration outside of the suppression range. A similar effect was found for the decisional criterion (Cr), which was correlated with suppression (positive) and facilitation (negative). All together, our results indicate that facilitation exists at the periphery when the target-flanker distance is properly scaled. Thus, our results indicate that collinear facilitation is a common phenomenon that exists in both the periphery and fovea. The suppression range indicates that the perceptual receptive field increases with increasing eccentricity. Our results provide a working hypothesis that explains the functional differences found between the fovea and the periphery. This supports the basic phenomena underlying visual perception, such as collinear facilitation, visual crowding, and backward masking.

Perceptual learning leads to long lasting visual improvement in patients with central vision loss

“…Other studies used a Yes/No task with eccentric stimuli and found collinear facilitation (Lev & Polat, 2011;Maniglia et al, 2011). We attempted to replicate these findings with MD patients since this task may be advantageous when compared to a temporal-2AFC task.…”

“…We attempted to replicate these findings with MD patients since this task may be advantageous when compared to a temporal-2AFC task. In fact, the latter may be limited by the requirement to maintain fixation between the two temporal intervals (Lev & Polat, 2011). In independent blocks, stimuli were presented either on the PRL or the non-PRL.…”

“…First, simulation studies showed that threshold estimation with a temporal-2AFC Kershaw, 1985;Taylor & Creelman, 1967). Second, when used with parafoveal stimuli, performance may be limited by the subjects' ability to maintain fixation between the first and the second interval (Lev & Polat, 2011), a problem that becomes insidious in MD patients that have peripheral and often unstable fixation.…”

Representation of central and peripheral vision in the primate cerebral cortex: Insights from studies of the marmoset brain

“…The psychophysics studies by Xing and Heeger (2000) and Petrov et al (2005) both demonstrated that the strength of surround suppression increases with eccentricity up to the 10 • eccentricity that was studied, but their data do not agree on whether surround suppression is present at the fovea. It has also been debated if surround facilitation operates at the peripheral visual field (Xing and Heeger, 2000;Williams et al, 2002;Lev and Polat, 2011). Using electrophysiology, Shushruth et al (2009) quantified surround suppression in macaque V1 and V2, but failed to find significant correlations with eccentricity (within 10 • eccentricity).…”

Individual differences in the dynamics of collinear facilitation?

“…Since Polat & Sagi (1993) first demonstrated both facilitation and suppression with such an arrangement, a multitude of spatial (Polat & Sagi 1994;Polat 2009;Polat et al 1998;Zenger-Landolt & Koch 2001;Mizobe et al 2001;Freeman et al 2001;Woods et al 2002;Freeman et al 2004;Giorgi et al 2004;Polat et al 2005;Polat & Sagi 2007;Shani & Sagi 2005;Huang et al 2006;Huang & Hess 2007;Huang et al 2012;Huang & Hess 2008;Sterkin et al 2008;Katkov & Sagi 2010;Wu & Chen 2010;Kéita et al 2011;Lev & Polat 2011;Jachim et al 2015) and temporal (Tanaka & Sagi 1998;Polat & Sagi 2006;Cass & Alais 2006;Huang & Hess 2008;Sterkin et al 2009;Li et al 2010;Sterkin et al 2012) combinations of target and flanker designs have been developed.…”