Brain Development Questions
1. This early neurodevelopmental structure will form the cerebral hemispheres:
- A. diencephalon
- B. telencephalon
- C. mesencephalon
- D. metencephalon
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Correct answer: B
The nervous system forms from the neural tube during neural development. As the neural tube matures, it develops several vesicles; these give rise to specific parts of the nervous system. The telencephalon forms the cerebral hemispheres, including the cerebral cortex and a number of subcortical structures.
2. This neural tube structure will eventually form the pons and cerebellum:
- A. prosencephalon
- B. diencephalon
- C. mesencephalon
- D. metencephalon
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Correct answer: D
The pons and cerebellum form from the metencephalon, a secondary vesicle of the neural tube.
3. During prenatal neural development, the primary action of GABA is:
- A. inhibitory
- B. excitatory
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Correct answer: B
Although GABA is widely known as the brain's main inhibitory neurotransmitter, in early embryonic and neonatal development, GABA is primarily excitatory. GABA is excitatory early on because immature neurons contain a high concentration of chloride ions inside the cell. When GABA binds to its receptors, chloride flows out of the neuron, causing the cell to depolarize—making it more likely to fire. Mature neurons have lower levels of internal chloride and GABA is inhibitory.
4. Spina bifida is a disorder that results from disrupted formation of which of the following structures during early embryonic development?
- A. meninges
- B. neural crest
- C. vertebral arch
- D. neural tube
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Correct answer: D
Spina bifida results from the incomplete closure or disruption in the formation of the neural tube during early embryonic development. The neural tube is the precursor to the brain and spinal cord, and when it fails to close properly, it can lead to defects such as spina bifida.
5. Which specialized structure, derived from ectoderm, forms during early embryonic development and eventually gives rise to the neural tube?
- A. neural crest
- B. notochord
- C. somite
- D. neural plate
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Correct answer: D
The neural plate is a thickened region of ectoderm that appears around week 3 of development. It folds inward to form the neural groove and neural folds, which then fuse to become the neural tube---the precursor to the brain and spinal cord.
6. This neural tube structure eventually forms the thalamus, hypothalamus, epithalamus, and subthalamus:
- A. telencephalon
- B. metencephalon
- C. mesencephalon
- D. diencephalon
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Correct answer: D
The diencephalon is the neural tube structure that gives rise to the thalamus, hypothalamus, and several other subcortical structures. It develops from the prosencephalon.
7. At around the fourth week of neural development, the neural tube expands into three bulges known as the:
- A. primary vesicles
- B. ventricles
- C. neural crests
- D. meninges
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Correct answer: A
As the neural tube closes, bulges begin to appear and they gradually become more noticeable. During the fourth week, there are three of these bulges present. They are called the primary vesicles. They are the prosencephalon, the mesencephalon, and the rhombencephalon.
8. During neural development, these glial cells act as scaffolding that new neurons use to travel from their site of origin to their final destination in the brain:
- A. radial glia
- B. oligodendrocytes
- C. astrocytes
- D. satellite cells
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Correct answer: A
Radial glia are involved in neurogenesis and neural development. They generate new neurons and also provide a scaffold that newborn neurons use to travel from their site of origin to their final destination in the brain.
9. The strongest non-genetic risk factor associated with spina bifida is:
- A. maternal calcium deficiency
- B. excess maternal vitamin C intake
- C. inadequate intake of folate or folic acid during pregnancy
- D. elevated maternal cholesterol levels
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Correct answer: C
There are a number of non-genetic risk factors for spina bifida, but the best established one is inadequate intake of folate or folic acid before and during early pregnancy. Although it’s not completely clear why low folate levels are linked to spina bifida, folate plays important roles in neural development and thus a deficiency is thought to have the potential to interfere with healthy development.
10. This is the typically the most severe form of spina bifida; it can result in complications and disability:
- A. spina bifida occulta
- B. meningocele
- C. myelomeningocele
- D. spina bifida pernicia
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Correct answer: C
Spina bifida is a birth defect that involves disrupted formation of a structure called the neural tube. There are three types of spina bifida: myelomeningocele, meningocele, and spina bifida occulta. The latter two forms do not typically cause any symptoms. Myelomeningocele is typically the most severe form, and is more likely to result in complications and/or disability.
11. During early neural development, the prosencephalon gives rise to which secondary vesicles?
- A. mesencephalon and metencephalon
- B. diencephalon and telencephalon
- C. metencephalon and myelencephalon
- D. diencephalon and mesencephalon
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Correct answer: B
The prosencephalon forms the diencephalon and telencephalon. The telencephalon will become the cerebral hemispheres, and the diencephalon will eventually consist of the thalamus, hypothalamus, epithalamus, and subthalamus.
12. The delayed maturation of brain regions involved in impulse control and long-term planning has been linked in part to the continued development of which process?
- A. neurogenesis
- B. myelination
- C. apoptosis
- D. cell migration
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Correct answer: B
Myelination in parts of the prefrontal cortex involved in impulse control, long-term planning, and decision-making continues through adolescence and is not typically complete until adulthood. As a result, the neural circuits that support these functions may operate less efficiently in adolescents than in adults, potentially contributing to some stereotypical aspects of teen behavior.
13. Which condition below is caused by the failure of the neural tube to form or close properly in early neural development:
- A. Phenylketonuria
- B. Fragile X syndrome
- C. Spina bifida
- D. Down syndrome
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Correct answer: C
Spina bifida is a birth defect that involves disrupted formation of a structure called the neural tube. The neural tube forms in early neural development, and eventually will become the brain and spinal cord. In spina bifida, the neural tube either does not form or close properly.
14. The development of the nervous system begins when an area of the ectoderm thickens and forms what is known as the:
- A. notochord
- B. neural crest
- C. spinal sheath
- D. neural plate
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Correct answer: D
The development of the nervous system begins at around the third week of embryonic development, when an area of the ectoderm, or the outer tissue layer of the embryo, thickens and forms what is known as the neural plate.
15. During neural development, more neurons are initially produced than are needed. Which process eliminates many of these excess neurons?
- A. differentiation
- B. apoptosis
- C. axon guidance
- D. cell migration
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Correct answer: B
The developing brain typically produces more neurons than it ultimately needs, and neurons that fail to establish appropriate connections or receive sufficient survival signals may undergo programmed cell death, also known as apoptosis.
