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Course: MCAT > Unit 4

Lesson 1: Foundations of behavior passages

A virus which affects mouse muscles


Viruses are infectious agents that have the ability to produce a variety of structural and biochemical changes in the cells that they infect. A researcher is studying a virus that causes the selective loss of lower motor neurons in the nervous system. He is interested in seeing how changes to motor functions progress over time after infection with the virus. He believes that there will be a dose-response relationship, and that functional deficits will vary considerably depending on the amount of virus involved in the infection. To study this, he administers different amounts of the virus to different groups of mice. At a series of time points after infection, he assesses the mice with a battery of behavioral tests of neurological functions, and performs electrical tests on their nerves and muscles. At each timepoint, he also performs the tests on a group of mice that were not administered the virus. He finds that there are associations between the amounts of virus administered and speed of progression of behavioral and electrical abnormalities. The results from his study are outlined in Table 1.
Table 1
GroupDays to 50% behavior deficitsDays to 50% electrical deficits
Controln/a (no deficits)n/a (no deficits)
Smallest viral dose2426
Medium viral dose1918
Largest viral dose75
What are the target cells of lower motor neurons?
Choose 1 answer: