How do we see in 3 dimensions? Sterovision
Retinal Disparity Objects that are far or near project slightly different images on our retinas. This creates “retinal disparity”, which provides clues to distance.
To Achieve Stereovision, Our Eyes Must Converge on a Point Convergence point Zero disparity Negative disparity Positive disparity
The Convergence Point and Disparity Positive disparity Convergence point Zero disparity Negative disparity
How does the brain process the images from the two retinas?
Visual aferences
Ocular Dominance Columns Orientation specificity Eye specificity
Ocularity of Neurons in V1 Monocular neurons respond to the activity of one eye, either the right eye or the left eye. Binocular neurons respond to the simultaneous activity of both eyes.
Monocular Neurons Activated by one eye only Example is left eye monocular neuron LGN LGN Inactive Active when left eye is stimulated
Stimulating only one eye is not sufficient to activate Binocular Neurons Stimulating only one eye is not sufficient to activate LGN LGN Inactive Inactive
Activated only when both eyes are stimulated Binocular neuron Activated only when both eyes are stimulated LGN Active!
The right and left eyes project to different adjacent regions of the visual cortex: Ocular dominance columns
Formation of Ocular Dominance Depends on Activity Visual Cortex Left eye closed Right Left