Which description best fits a smooth cortex due to neuronal migration disorder?

Which description best fits a smooth cortex due to neuronal migration disorder?

• A. Hydrocephalus
• B. Periventricular nodular heterotopia
• C. Dandy-Walker malformation
• D. Lissencephaly

Answer: (D)

The main idea here is how neuronal migration affects the surface of the cerebral cortex. When neurons fail to migrate properly to form the layered cortex, the brain ends up with far fewer gyri and sulci, producing a smooth appearance known as lissencephaly. This condition literally means a “smooth brain,” and it results from disruptions in the migration process during development, often during mid-gestation. The cortex in lissencephaly is thick and lacks the normal folds, leading to severe developmental delay and seizures. Other descriptions describe different migration-related problems that don’t produce a globally smooth cortex. For example, a condition with a smooth surface isn’t simply due to enlarged ventricles or a posterior fossa malformation; those scenarios involve hydrocephalus or hindbrain anomalies rather than a uniform lack of gyri. A periventricular nodular heterotopia shows misplaced clusters of neurons along the ventricular lining rather than a completely smooth cortex. Dandy-Walker malformation centers on cerebellar and posterior fossa abnormalities with enlarged fourth ventricle and vermian hypoplasia, not a smooth cerebral surface. Therefore, the smooth cortex best fits lissencephaly, a neuronal migration disorder.

The main idea here is how neuronal migration affects the surface of the cerebral cortex. When neurons fail to migrate properly to form the layered cortex, the brain ends up with far fewer gyri and sulci, producing a smooth appearance known as lissencephaly. This condition literally means a “smooth brain,” and it results from disruptions in the migration process during development, often during mid-gestation. The cortex in lissencephaly is thick and lacks the normal folds, leading to severe developmental delay and seizures.

Other descriptions describe different migration-related problems that don’t produce a globally smooth cortex. For example, a condition with a smooth surface isn’t simply due to enlarged ventricles or a posterior fossa malformation; those scenarios involve hydrocephalus or hindbrain anomalies rather than a uniform lack of gyri. A periventricular nodular heterotopia shows misplaced clusters of neurons along the ventricular lining rather than a completely smooth cortex. Dandy-Walker malformation centers on cerebellar and posterior fossa abnormalities with enlarged fourth ventricle and vermian hypoplasia, not a smooth cerebral surface. Therefore, the smooth cortex best fits lissencephaly, a neuronal migration disorder.