How many layers does the LGN have?

• A. Four layers.
• B. Eight layers.
• C. Two layers.
• D. Six layers.

Answer: (D)

The lateral geniculate nucleus is organized into six distinct layers in each side of the brain, reflecting two parallel visual pathways. Layers 1 and 2 are magnocellular, handling motion and broad, rapid signals, while layers 3 through 6 are parvocellular, specializing in color and fine detail. Between these main layers lie small koniocellular regions, which contribute additional processing but don’t change the standard count. This six-layer arrangement is the conventional anatomy for primates, including humans.