On-off selectivity and asymmetry in apparent contrast: An adaptation study

Area of Science:

• Visual perception
• Neuroscience
• Image processing

Background:

• Previous research demonstrated simultaneous contrast-contrast effects tuned for contrast polarity.
• Prolonged viewing of high-contrast stimuli reduces perceived contrast, a phenomenon known as contrast adaptation.

Purpose of the Study:

• To investigate whether contrast aftereffects exhibit selectivity for luminance polarity.
• To determine if adaptation aftereffects show asymmetry based on adapter polarity.
• To assess the influence of dichoptic presentation on polarity selectivity and asymmetry.

Main Methods:

• Utilized texture patterns with sparse bright/dark elements to selectively activate on or off sensors.
• Examined contrast aftereffects using these textures to test for luminance polarity selectivity.
• Investigated adaptation aftereffects under monocular and dichoptic presentation conditions.

Main Results:

• Contrast aftereffects were found to be selective for luminance polarity (polarity selectivity).
• Adaptation aftereffects demonstrated asymmetry, varying with the polarity of the adapting stimulus.
• Dichoptic presentation reduced, but did not eliminate, polarity selectivity and asymmetry.

Conclusions:

• Suprathreshold contrast perception is influenced by polarity selectivity and asymmetry in adaptation.
• These findings suggest that both monocular and binocular units contribute to contrast perception and adaptation.
• The results support a model where visual adaptation involves interactions between different neural pathways.