Disrupted neuronal migration during cortical development most directly leads to which outcome?

Disrupted neuronal migration during cortical development most directly leads to which outcome?

• A. Disorganized cortical layering
• B. Hyperproliferation of glia
• C. Excessive myelination
• D. Normal layering

Answer: (A)

Neuronal migration moves developing neurons from the ventricular zone to the cortical plate to build the layered structure of the neocortex. When this migration is disrupted, neurons don’t reach their proper layers and settle in incorrect locations, producing a cortex with disorganized layering. This misplaced lamination underlies conditions like lissencephaly and cortical heterotopia, and it explains why cortical architecture is scrambled and function is impaired. Hyperproliferation of glia isn’t the direct outcome of disrupted neuronal migration, and excessive myelination occurs later and reflects different processes. Normal layering would only occur if migration were intact.

Neuronal migration moves developing neurons from the ventricular zone to the cortical plate to build the layered structure of the neocortex. When this migration is disrupted, neurons don’t reach their proper layers and settle in incorrect locations, producing a cortex with disorganized layering. This misplaced lamination underlies conditions like lissencephaly and cortical heterotopia, and it explains why cortical architecture is scrambled and function is impaired. Hyperproliferation of glia isn’t the direct outcome of disrupted neuronal migration, and excessive myelination occurs later and reflects different processes. Normal layering would only occur if migration were intact.