Question

What is the function of the rostral migratory stream?

A To move newly born cells from the SVZ to the olfactory bulb

B To move old, apoptotic cells from the hippocampus to the SVZ

C To move newly born cells from the SGZ to the hippocampus

D To move newly born cells from the fourth ventricle to the cerebellum

Which of the following is false regarding the role of complement in the nervous system?

A Complement tags synapses for removal by microglia

B Complement has no effect on adult neurons

C Astrocyte signaling is necessary for complement upregulation in neurons

D Knockout of complement proteins impairs the ocular dominance process in LGN

What is false of CNS immunity?

A Suppressing CNS immunity is beneficial in MS and detrimental in cognitive processing

B Suppression of microglia results in increased production of trophic factors that support neuronal survival

C Microglia are primary mediators of inflammation in multiple sclerosis

D Loss of only B cells is primarily responsible for deficits in learning and memory

Answer 1

Q1- What is the function of the rostral migratory stream?

Correct answer is (A) - To move newly born cells from the SVZ to the olfactory bulb

Explanation: The rostral migratory stream is a specialized migratory route found in the brain of some animals along which neuronal precursors that originated in the subventricular zone (SVZ) of the brain migrate to reach the main olfactory bulb (OB).When the neurons reach the OB they differentiate into GABAergic interneurons as they are integrated into either the granule cell layer or periglomerular layer.

Q2 - Which of the following is false regarding the role of complement in the nervous system?

Correct answer is (B) - Complement has no effect on adult neutrons.

Explanation: Complement system is the fundamental component of innate immunity where it participates in the tagging of inappropriate synapses for elimination by microglial phagocytes. A number of neurodegenerative diseases are associated with aberrant activation of complement in mature brain, stimulating synapse loss in adult neurons, indicating that complement does effects adult neurons.

Q3 - What is false of CNS immunity?

Correct answer is (B) - Supression of microglia results in increased production of trophic factors that support neuronal survival.

Explanation: The existence of neuron type-specific pro-survival mechanisms in glutamatergic neurons was recently highlighted by the identification of a pro-survival pathway that was largely restricted to cortical principal neurons of layer V, which require trophic support from microglia to survive during early postnatal development. Microglia secrete IGF1, which binds to IGF1R on immature layer V neurons and activates the IRS1/PI3K/Akt1 cascade inhibiting caspase-3-dependent apoptosis. This study indicates that microglia actually produce factors that supports survival and their supression would reduce the production of such factors.