Final answer:
The respiratory response to O2 in REM sleep is not typically depressed; it resembles those observed in wakefulness. In individuals with certain sleep disorders, such as sleep apnea, respiratory activity can be depressed during sleep.
Step-by-step explanation:
The question regarding the response to O2 in REM asks about whether there is a depressed respiratory response during the REM phase of sleep. REM, or rapid eye movement sleep, is a period characterized by brain waves very similar to those during wakefulness and is when dreaming typically occurs. In normal individuals, muscle systems except for those essential for circulation and respiration experience paralysis. However, in contrast to non-REM (NREM) sleep, REM does not typically feature depressed respiratory activity, and the patterns can resemble those seen during wakefulness.
It is interesting to note that REM sleep may play a significant role in how the brain processes emotional experiences from wakefulness, as REM rebound — an increase in REM sleep following deprivation — might help to reduce the emotional impact of stressful events. However, when it comes to sleep disorders such as obstructive sleep apnea, the respiratory response can indeed become depressed during sleep, which is a potential concern that would need to be addressed clinically.