Sleep Oscillations (IMAGE) Max-Planck-Gesellschaft Caption Sleep constitutes an uninterrupted epoch of regular oscillations between two spectral profiles. The figure shows the time evolution of the color coded delta/beta power spectral ratio (delta and beta being the 0-4Hz and 10-30Hz frequency bands respectively). The delta/beta ratio was measured piecewise over 10s-long data segments in 1s steps. Rows along x represent successive 30-min segments running continuously (L to R) from top to bottom. Following lights off (at 19:00), the animals assume a typical sleep posture and oscillations in delta/beta increase in amplitude. These oscillations later gradually decrease followed by the waking up of the animal. Credit MPI f. Brain Research/ S. Junek Usage Restrictions Use of images is limited to editorial coverage of scientific topics relating to the activities of the Max Planck Society. Any kind of commercial use (including, in particular, the exploitation of images by means of sale or incorporation in image databases or image catalogues) as well as any promotional use/use for merchandise purposes, disclosure to third parties or granting of related rights to third parties is expressly not permitted. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.