title: Sensory perception during sleep in humans: a magnetoencephalograhic study.
abstract: We reported the changes of brain responses during sleep following auditory, visual, somatosensory and painful somatosensory stimulation by using magnetoencephalography (MEG). Surprisingly, very large changes were found under all conditions, although the changes in each were not the same. However, there are some common findings. Short-latency components, reflecting the primary cortical activities generated in the primary sensory cortex for each stimulus kind, show no significant change, or are slightly prolonged in latency and decreased in amplitude. These findings indicate that the neuronal activities in the primary sensory cortex are not affected or are only slightly inhibited during sleep. By contrast, middle- and long-latency components, probably reflecting secondary activities, are much affected during sleep. Since the dipole location is changed (auditory stimulation), unchanged (somatosensory stimulation) or vague (visual stimulation) between the state of being awake and asleep, different regions responsible for such changes of activity may be one explanation, although the activated regions are very close to each other. The enhancement of activities probably indicates two possibilities, an increase in the activity of excitatory systems during sleep, or a decrease in the activity of some inhibitory systems, which are active in the awake state. We have no evidence to support either, but we prefer the latter, since it is difficult to consider why neuronal activities would be increased during sleep.
authors: Department of Integrative Physiology, National Institute for Physiological Sciences, Myodaiji, Okazaki 444-8585, Japan. kakigi@nips.ac.jp
authors: Ryusuke
authors: R
authors: Kakigi
authors: Daisuke
authors: D
authors: Naka
authors: Tomohiro
authors: T
authors: Okusa
authors: Xiohong
authors: X
authors: Wang
authors: Koji
authors: K
authors: Inui
authors: Yunhai
authors: Y
authors: Qiu
authors: Tuan Diep
authors: TD
authors: Tran
authors: Kensaku
authors: K
authors: Miki
authors: Yohei
authors: Y
authors: Tamura
authors: Thi Binh
authors: TB
authors: Nguyen
authors: Shoko
authors: S
authors: Watanabe
authors: Minoru
authors: M
authors: Hoshiyama
mesh_terms: D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005074:Evoked Potentials, Visual / Q000502:physiology; D005260:Female; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000502:physiology; D010470:Perceptual Masking / Q000502:physiology; D012890:Sleep / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*