The horizontal effect in suppression: Anisotropic overlay and surround suppression at high and low speeds

Abstract

When a pattern of broad spatial content is viewed by an observer, the multiple spatial components in the pattern stimulate detecting-mechanisms that suppress each other. This suppression is anisotropic, being relatively greater at horizontal, and least at obliques (the "horizontal effect"). Here, suppression of a grating by a naturalistic (1/f) broadband mask is shown to be larger when the broadband masks are temporally similar to the target's temporal properties, and generally anisotropic, with the anisotropy present across all spatio-temporal parings tested. We also show that both suppression from within the region of the test pattern (overlay suppression) and from outside of this region (surround suppression) show the horizontal-effect anisotropy. We conclude that these suppression effects stem from locally-tuned and anisotropically-weighted gain-control pools.

Psychophysical analysis of three separate anisotropic patterns in vision : putting visual reference frames in conflict to study the class 1 and 2 oblique effects and the horizontal effect.

“…There was no interaction between head tilt and orientation: Table 13) were analyzed. The data show us that the top-down cognition did not have an effect on the results as they are still "in-between" gravitational and retinal coordinates and do not shift (Essock, DeFord, Hansen & Sinai, 2003;Hansen & Essock, 2004;Essock, Haun & Kim 2009;Kim, Haun & Essock, 2010). It occurs with stimuli that are broadband, both in terms of in spatial frequency and orientation content, which I used in the matching task.…”

“…The horizontal effect then, serves to whiten a natural scene by suppressing horizontal content the most and oblique input the least, which is a highly beneficial step in the coding process. This means that typical natural scene content is suppressed and less-prevalent content is made relatively more salient (Hansen & Essock, 2004;Haun, Hansen, & Essock, 2006;Essock et al, 2009;Kim, Haun, & Essock, 2010; see also Schwartz & Simoncelli, 2001;Wainwright, 1999).…”

“…The importance of patterncentric coordinates is in agreement with the theory that the horizontal effect serves to "whiten" a natural scene. Because the natural scenes contain most orientation content (Fourier power) at horizontal, second most at vertical, and least at oblique orientations, the horizontal effect normalizes a natural scene by suppressing horizontal content the most and oblique input the least, so that typical natural scene content is suppressed and less-prevalent content is made relatively more salient (Hansen & Essock, 2004;Haun, Hansen, & Essock, 2006;Essock et al, 2009;Kim, Haun, & Essock, 2010).…”

What we see changes how we see : analyzing the plasticity of the horizontal effect.

“…Lines and edges of different sizes and orientations are the elementary building blocks of the natural world and, as was discovered later, are not-coincidentally the fundamental encoding mechanisms for the cortical processing of images (Hubel & Weisel, 1959, 1962. For the past decade, Essock and colleagues have been investigating the relationship between the processing of orientation by the human visual system and how this processing relates to the orientation content of the natural environment (Essock, DeFord, Hansen, & Sinai, 2003;Essock, Haun, & Kim, 2009;Hansen & Essock, 2004;Hansen & Essock, 2005;Hansen & Essock, 2006;Kim, Haun, & Essock, 2010). For almost 100 years we have known that humans see cardinal orientations (horizontal and vertical) better than oblique orientations (Appelle, 1972;Campbell & Kulikoski, 1966;Corwin, Moskowitz-Cook, & Green, 1977;Emsley, 1925;Essock, 1982;Hamblin & Winser, 1927;Higgins & Stultz, 1948;Leibowitz, 1953;Shlaer, 1937).…”

“…Many authors have also noted that natural scene statistics show a relationship to this differential visual processing of orientations (Coppola, Purves, McCoy, & Purves, 1998;Hansen & Essock, 2004;Keil & Cristobal, 2000;Switkes, Mayer, & Sloan, 1978). More recent work by Essock and colleagues has determined that orientation processing is more complex than it once appeared; when presented in a broadband, naturalistic context, human perception of horizontal orientations is actually worst and oblique orientations are perceived best Essock, Haun, & Kim, 2009;Hansen & Essock, 2004Kim, Haun, & Essock, 2010). This finding has further extended the relationship between visual encoding and natural scene statistics as the differential perception of orientations in broadband scenes closely matches their differential representation in the natural environment (Essock, Haun, & Kim, 2009;.…”