Two studies being presented today shed light on the importance of rapid eye movement (REM) sleep.
A study (#1284) being presented as a poster until 12:15 p.m. Pacific Time reports that in both men and women, REM appears to modulate negative affect; in females, REM also may modulate negative autobiographical memories. According to the study’s author, the results suggest that severe depression in women may be associated with an excess of REM sleep.
Another study (#0379) that will be presented this afternoon as an oral presentation suggests that REM sleep may enhance the brain’s empathetic capacity toward positive emotions. Results show that participants who did not take an afternoon nap displayed an amplified reaction to expressions representing anger and fear when tested on a face-rating task at 5 p.m. In contrast, participants who had an afternoon nap opportunity lasting 60 to 90 minutes displayed an increased receptiveness to happy facial expressions following sleep; however, this beneficial effect was found only in participants who achieved REM sleep during the nap.
The American Academy of Sleep Medicine reports that sleep involves multiple stages that make up a sleep cycle. Each complete cycle lasts about 90 to 110 minutes; most adults will go through four to six cycles in a full night of sleep. REM sleep tends to be the final stage of the sleep cycle in normal adult sleep. Most dreams occur during this sleep stage. Find more about the stages of sleep on SleepEducation.com.
You can download the SLEEP 2009 abstract supplement as an 11 MB file in PDF format.