1. How do we see in 3 dimensions?
Sterovision

2. Retinal Disparity
Objects that are far or near project slightly different images on our retinas.
This creates “retinal disparity”, which provides clues to distance.

3. To Achieve Stereovision, Our Eyes Must Converge on a Point
Convergence point
Zero disparity
Negative disparity
Positive disparity

4. The Convergence Point and Disparity
Positive disparity
Convergence point
Zero disparity
Negative disparity

5. How does the brain process the images from the two retinas?

6. Visual aferences

8. Ocular Dominance Columns
Orientation
specificity
Eye
specificity

9. 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.

10. Monocular Neurons Activated by one eye only
Example is left eye monocular neuron
LGN
LGN
Inactive
Active when left eye is stimulated

11. Stimulating only one eye is not sufficient to activate
Binocular Neurons
Stimulating only one eye is not sufficient to activate
LGN
LGN
Inactive
Inactive

12. Activated only when both eyes are stimulated
Binocular neuron
Activated only when both eyes are stimulated
LGN
Active!

13. The right and left eyes project to
different adjacent regions of the visual cortex:
Ocular dominance columns

14. Formation of Ocular Dominance Depends on Activity
Visual Cortex
Left eye closed
Right
Left