TY - JOUR T1 - Activity of Midbrain Reticular Formation and Neocortex during the Progression of Human Non-Rapid Eye Movement Sleep JF - The Journal of Neuroscience JO - J. Neurosci. SP - 10065 LP - 10073 DO - 10.1523/JNEUROSCI.19-22-10065.1999 VL - 19 IS - 22 AU - Naofumi Kajimura AU - Makoto Uchiyama AU - Yutaka Takayama AU - Sunao Uchida AU - Takeshi Uema AU - Masaaki Kato AU - Masanori Sekimoto AU - Tsuyoshi Watanabe AU - Toru Nakajima AU - Satoru Horikoshi AU - Kenichi Ogawa AU - Masami Nishikawa AU - Masahiko Hiroki AU - Yoshihisa Kudo AU - Hiroshi Matsuda AU - Masako Okawa AU - Kiyohisa Takahashi Y1 - 1999/11/15 UR - http://www.jneurosci.org/content/19/22/10065.abstract N2 - To clarify the neural correlates and brain activity during the progression of human non-rapid eye movement (NREM) sleep, we examined the absolute regional cerebral blood flow (rCBF) during light and deep NREM sleep and during wakefulness in normal humans using positron emission tomography with H215O. Relative changes in rCBF during light and deep NREM sleep in comparison to the rCBF during wakefulness were also analyzed. During light NREM sleep, the rCBF in the midbrain, in contrast to that in the pons and thalamic nuclei, did not decrease when compared to that during wakefulness, whereas rCBF decreased in the left medial frontal gyrus, left inferior frontal gyrus, and left inferior parietal gyrus of the neocortex. During deep NREM sleep, the rCBF in the midbrain tegmentum decreased, and there was a marked and bilateral decrease in the rCBF in all neocortical regions except for the perirolandic areas and the occipital lobe. There have been three groups of brain structures, each representing one type of deactivation during the progression of NREM sleep. The activity of the midbrain reticular formation is maintained during light NREM sleep and therefore represents a key distinguishing characteristic between light and deep NREM sleep. Selective deactivation of heteromodal association cortices, including those related to language, occurs with increasingly deep NREM sleep, which supports the recent theory that sleep is not a global, but it is a local process of the brain. ER -