Stereoscopic vision: solving the correspondence problem.

Area of Science:

• Neuroscience
• Visual Perception
• Computational Neuroscience

Background:

• Early visual neurons respond to horizontal disparity, a cue for depth.
• Stereopsis, or conscious depth perception, is not always evoked by horizontal disparity.
• The neural mechanisms distinguishing true from false binocular matches remain unclear.

Purpose of the Study:

• To investigate how the brain processes horizontal disparity.
• To determine the neural correlates of conscious depth perception.
• To identify the role of the inferior temporal cortex in resolving binocular ambiguity.

Main Methods:

• Electrophysiological recordings from neurons in the primate inferior temporal cortex.
• Presentation of visual stimuli with varying degrees of horizontal disparity.
• Correlation analysis between neuronal activity and behavioral reports of depth perception.

Main Results:

• Neurons in early visual areas responded to horizontal disparity even without stereopsis.
• Activity in the inferior temporal cortex neurons correlated with conscious depth perception.
• False binocular matches were effectively discarded at this higher visual processing stage.

Conclusions:

• The primate inferior temporal cortex plays a critical role in conscious depth perception.
• This brain region is involved in resolving binocular ambiguity by discarding false matches.
• Neural activity in the inferior temporal cortex reflects the subjective experience of depth.