After a cut through the midbrain separates the forebrain and part of the midbrain from all the lower structures, an animal ____.
A) stops sleeping
B) sleeps a normal amount per day, but lacks REM sleep
C) enters a prolonged state of sleep
D) alternates rapidly between sleep and wakefulness

Question

Quizplus · Accepted Answer

This cut would disconnect the forebrain and midbrain regions responsible for arousal and wakefulness from lower brainstem regions that promote sleep. Therefore, the animal would enter a prolonged state of sleep until the cut is resolved or healed. Option A is incorrect because the animal would actually sleep more after the cut. Option B is incorrect because the cut would also disconnect the brainstem structures responsible for REM sleep, resulting in no REM sleep. Option D is incorrect because the animal would not be able to alternate between sleep and wakefulness due to the cut.

After a Cut Through the Midbrain Separates the Forebrain and Part