Complete interocular transfer of motion adaptation effects on motion coherence thresholds

Area of Science:

• Neuroscience
• Visual Perception
• Computational Neuroscience

Background:

• Human binocularity is studied using interocular transfer (IOT) of visual aftereffects.
• Extrastriate visual areas (e.g., MT) are uniformly binocular, while V1 cells vary in binocularity.
• Complete IOT is expected for extrastriate-mediated aftereffects, unlike partial transfer (70%) for V1-mediated aftereffects.

Purpose of the Study:

• Investigate the role of extrastriate areas in motion perception.
• Determine if IOT of motion aftereffects is complete, as predicted by extrastriate involvement.
• Differentiate mechanisms of motion incoherence aftereffects and classical motion aftereffects.

Main Methods:

• Measured IOT of the motion incoherence aftereffect in four human observers.
• Used partially coherent random dot kinematograms (RDKs) for adaptation and testing.
• Measured motion coherence thresholds after interocular and intraocular adaptation.
• Compared IOT of motion incoherence aftereffect with classical motion aftereffect.

Main Results:

• Complete transfer of the motion incoherence aftereffect was observed (equal threshold elevation for interocular and intraocular adaptation).
• Partial or absent transfer was found for the classical motion aftereffect under identical conditions.
• These findings indicate a significant role for extrastriate areas in motion perception.

Conclusions:

• The complete IOT of the motion incoherence aftereffect supports the significant role of extrastriate areas in motion processing.
• The differing IOT patterns suggest that the motion incoherence aftereffect and classical motion aftereffect involve distinct neural mechanisms.