Editing Rapid eye movement sleep (section)

==== Forebrain ====

Research in the 1990s using [[positron emission tomography]] (PET) confirmed the role of the brain stem and suggested that, within the [[forebrain]], the [[limbic]] and [[paralimbic cortex|paralimbic]] systems showed more activation than other areas.<ref name=MatarazzoEtAl2011 /> The areas activated during REM sleep are approximately inverse to those activated during non-REM sleep<ref name=HobsonEtAl2000 /> and display greater activity than in quiet waking. The "anterior paralimbic REM activation area" (APRA) includes areas linked with [[emotion]], memory, fear and sex, and may thus relate to the experience of dreaming during REMS.<ref name=EPS2011 /><ref>{{cite journal | vauthors = Nofzinger EA, Mintun MA, Wiseman M, Kupfer DJ, Moore RY | title = Forebrain activation in REM sleep: an FDG PET study | journal = Brain Research | volume = 770 | issue = 1–2 | pages = 192–201 | date = October 1997 | pmid = 9372219 | doi = 10.1016/s0006-8993(97)00807-x | s2cid = 22764238 }}</ref> More recent PET research has indicated that the distribution of brain activity during REM sleep varies in correspondence with the type of activity seen in the prior period of wakefulness.<ref name=MatarazzoEtAl2011 />

The [[superior frontal gyrus]], [[medial frontal gyrus|medial frontal areas]], [[intraparietal sulcus]], and [[superior parietal lobule|superior parietal cortex]], areas involved in sophisticated [[mind|mental]] activity, show equal activity in REM sleep as in wakefulness. The [[amygdala]] is also active during REM sleep and may participate in generating the PGO waves, and experimental suppression of the amygdala results in less REM sleep.<ref>{{cite book | vauthors = Sanford LD, Ross RJ | chapter = Amygdalar regulation of REM sleep. | veditors = Mallick BN, Pandi-Perumal SR, McCarley RW, Morrison AR | title = Rapid eye movement sleep. | publisher = Cambridge University Press | location = Cambridge | date = July 2011 | pages = 110–120 }}</ref> The amygdala may also regulate cardiac function in lieu of the less active [[insular cortex]].<ref name=MatarazzoEtAl2011 />