Damage to which cortical area would most likely disrupt basic visual perception?

• A. Area 17
• B. Area 18
• C. Area 19
• D. Area 20

Answer: (A)

Processing of basic visual input starts in the primary visual cortex, located in the occipital lobe as Area 17 (V1). This region creates a retinotopic map and contains neurons that detect simple features like light, edges, and orientation. When Area 17 is damaged, those initial, fundamental aspects of seeing are lost, leading to cortical blindness or specific visual field defects because the brain’s first stage of processing visual information is compromised. The other areas are higher-order visual regions that handle more complex attributes such as form, color, motion, and object recognition; damage there tends to disrupt these advanced aspects rather than the basic sensation of seeing. Area 20, for example, is involved in object recognition in the inferior temporal cortex, not initial visual perception. Hence, damage to the primary visual cortex would most disrupt basic visual perception.