What are the major embryonic brain vesicles and their adult derivatives?

• A. Prosencephalon becomes the hindbrain; Mesencephalon becomes the forebrain.
• B. Prosencephalon (forebrain) → telencephalon and diencephalon; Mesencephalon → midbrain; Rhombencephalon → metencephalon and myelencephalon.
• C. Rhombencephalon becomes the cerebral hemispheres.
• D. Prosencephalon becomes the cerebral cortex only.

Answer: (B)

Early brain development forms three primary vesicles: forebrain (prosencephalon), midbrain (mesencephalon), and hindbrain (rhombencephalon). The forebrain splits into the telencephalon and diencephalon; the telencephalon becomes the cerebral hemispheres (including the cerebral cortex and related structures), while the diencephalon becomes key deep structures like the thalamus and hypothalamus. The midbrain remains as the midbrain. The hindbrain divides into the metencephalon and myelencephalon, with metencephalon producing the pons and cerebellum, and myelencephalon becoming the medulla oblongata. This mapping aligns with the described adult derivatives, making it the correct description.