In the inside-out organization of the cerebral cortex, early-born neurons populate which cortical layers?

In the inside-out organization of the cerebral cortex, early-born neurons populate which cortical layers?

• A. Deep layers
• B. Upper layers
• C. Middle layers
• D. All layers simultaneously

Answer: (A)

During cortical development, neurons are generated in a time-ordered sequence and migrate to their final positions along radial glial fibers. The earliest-born neurons settle in the deepest cortical layers. As neurogenesis continues, later-born neurons migrate past the earlier ones to occupy progressively more superficial layers. This inside-out pattern means the first population forms the deep layers, especially layer VI (and then V), while later waves fill layers IV, III, II, and I. So, early-born neurons populate the deep layers.

During cortical development, neurons are generated in a time-ordered sequence and migrate to their final positions along radial glial fibers. The earliest-born neurons settle in the deepest cortical layers. As neurogenesis continues, later-born neurons migrate past the earlier ones to occupy progressively more superficial layers. This inside-out pattern means the first population forms the deep layers, especially layer VI (and then V), while later waves fill layers IV, III, II, and I. So, early-born neurons populate the deep layers.