For a normally developed ocular dominance histogram, what does Column 7 represent?

• A. Contralateral eye only
• B. Ipsilateral eye only
• C. Equal input from both left and right eye
• D. No input

Answer: (B)

In a normal ocular dominance histogram, columns show how strongly neurons in the visual cortex respond to input from the two eyes, ranging from almost purely contralateral input on the left to almost purely ipsilateral input on the right. The far right column corresponds to neurons that respond only to the ipsilateral eye—there is no detectable input from the opposite eye. That’s why this column represents ipsilateral-eye-only input. A column in the leftmost position would be contralateral-eye-only, and the middle columns reflect varying degrees of mixture. A “no input” category isn’t part of a typical normal distribution.