Binocular sensory fusion is limited by spatial resolution

Area of Science:

• Vision science
• Neuroscience
• Perception

Background:

• Binocular sensory fusion is critical for stereoscopic vision.
• Its maximum spatial extent was previously believed to be limited to 1 degree at the fovea.

Purpose of the Study:

• To investigate the spatial extent of binocular sensory fusion.
• To explore the relationship between sensory fusion and stereoscopic depth perception.

Main Methods:

• Stimulation with low spatial frequency (coarse) detail.
• Measurement of the upper limit for sensory fusion and phase disparity.

Main Results:

• Binocular sensory fusion extent is at least 600% larger than previously thought when using coarse detail.
• A constant phase disparity limit of 90 degrees was observed.
• This limit corresponds to the monocular Rayleigh criterion for spatial resolution.

Conclusions:

• The upper limit for sensory fusion expands significantly with low spatial frequencies.
• Sensory fusion limits match stereoscopic depth perception limits at low spatial frequencies.
• A shared underlying mechanism for sensory fusion and stereoscopic depth perception is suggested.