Orientation-tuned surround-suppression is strongest within perceived 3D surfaces.

Area of Science:

• Visual perception
• Neuroscience
• Computational vision

Background:

• Perception of contrast is influenced by contextual factors.
• Orientation-tuned surround suppression (OTSS) demonstrates how surrounds with similar orientation suppress perceived contrast.
• This phenomenon is traditionally linked to horizontal interactions in the early visual cortex.

Purpose of the Study:

• To investigate the role of perceived three-dimensional (3D) structure in modulating OTSS.
• To determine if perceived depth or surface continuity is the primary factor influencing suppressive interactions.

Main Methods:

• Manipulating retinal disparity to alter perceived depth of surround elements relative to a central stimulus.
• Assessing the strength of OTSS under conditions where surrounds were perceived as part of the same or different 3D surfaces.
• Varying the perceived depth of the surround (behind or in front of the center).

Main Results:

• The strength of OTSS was significantly modulated by the perceived 3D surface structure of the scene.
• Placing the surround at a different retinal disparity (perceived depth) decreased OTSS.
• Suppressive interactions were strongest for surrounds perceived as continuous with the center's surface, and weaker for surrounds perceived as separate surfaces, irrespective of depth differences.

Conclusions:

• Perceived surface continuity, rather than just depth, is a critical factor in gating suppressive interactions in early vision.
• These findings suggest that higher-level perceptual organization can influence low-level neural processing.
• The results challenge simple models of horizontal interactions and highlight the role of surface perception in visual processing.