Netrin Was First Discovered in a Biochemical Assay for the Attraction

question 14

Multiple Choice

Netrin was first discovered in a biochemical assay for the attraction of vertebral commissural axons to floor plate. In mutants for the worm netrin homologue Unc6, sensory axons failed to project ventrally and motor neurons fail to project dorsally. This result suggested that:

• A) Unc6 can repel neurons as well as attract them.
• B) Unc6 and netrin have conserved roles as well as sequences.
• C) sensory neurons and motor neurons somehow interpret the Unc6 signal differently.
• D) All of the above
• E) None of the above

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Definitions:

Neurogenesis

The process of the formation of new neurons in the brain.

Split Brain

A condition resulting from surgery that isolates the brain’s two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them.

Corpus Callosum

The large band of neural fibers connecting the two hemispheres of the brain, facilitating communication and coordination between them.

Somatosensory Cortex

A region of the brain located in the parietal lobe that processes sensory information from various parts of the body, such as touch, temperature, and pain.