Analysis of the effect of pattern adaptation on pattern pedestal effects: a two-process model

Area of Science:

• Vision Science
• Perceptual Psychology
• Computational Neuroscience

Background:

• Understanding visual adaptation and masking is crucial for explaining contrast detection limits.
• Previous models of masking do not fully capture the complex effects of adaptation on contrast perception.

Purpose of the Study:

• To investigate the effects of visual adaptation on pattern contrast detection thresholds.
• To determine how adaptation influences the relationship between target and pedestal contrast (TvC function).
• To test a new model of adaptation and masking against existing frameworks.

Main Methods:

• Measured pattern contrast thresholds for vertical Gabor targets on vertical or horizontal pedestals.
• Determined TvC functions under no adaptation and after adaptation to vertical, horizontal, or plaid patterns.
• Analyzed asymmetric effects of adaptation on contrast detection using a modified masking model.

Main Results:

• Adaptation to vertical or plaid patterns raised thresholds for orthogonal pedestals across all contrasts.
• For same-orientation pedestals, adaptation raised thresholds only at low pedestal contrasts.
• A modified masking model, incorporating adaptor-produced divisive inhibition, successfully described these asymmetric effects.

Conclusions:

• Visual adaptation exhibits orientation-dependent effects on contrast detection.
• The findings support a model where adaptation influences divisive inhibition, explaining asymmetric masking effects.
• This research refines our understanding of the neural mechanisms underlying visual adaptation and contrast perception.