In some cortical areas, how many layers of cells may be present?

• A. 4
• B. 5
• C. 6
• D. 7

Answer: (C)

The cortex is organized into distinct layers, with a six-layer pattern in the neocortex. These six layers run from the outer surface to the deep white matter and each has characteristic cell types and connections that support how information is received, processed, and sent onward. The layers are commonly named I through VI, with layer IV often receiving the bulk of thalamic input in many sensory areas, and layer V providing major outputs to subcortical structures. While some cortical regions (like agranular or dysgranular areas, or parts of allocortex such as the hippocampus) don’t show the full six-layer arrangement, the standard and most widely taught lamination for many cortical areas is six layers, which is why six is the best answer.