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. Author manuscript; available in PMC: 2019 Sep 14.
Published in final edited form as: Nature. 2007 Oct 17;450(7168):420–424. doi: 10.1038/nature06310

Figure 3 |. In vivo photostimulation of Hcrt neurons drives sleep-to-wake transitions.

Figure 3 |

a, Representative EEG/EMG recordings showing awakenings after a single bout of photostimulation (15ms, 20Hz, 10s) in Hcrt::ChR2-mCherry and Hcrt::mCherry (control) animals during SWS (upper traces) and REM sleep (lower traces). Light stimulations are represented by horizontal bluebars. Awakening events are indicated by vertical black arrows according to the described criteria (see Methods). Panels (right) show representative relative cortical EEG power spectra corresponding to the SWS and REM sleep-to-wake transitions highlighted with boxes on the EEG traces (left). b, c, Latencies of wake transitions during SWS (b) and REM sleep (c) of Hcrt::ChR2-mCherry transduced animals (n = 7) and their controls (n = 6) after a single photostimulation bout at different frequencies (15-ms light pulses, at 1–30 Hz, during 10 s; ON, continuous light illumination of 10 s). Data analysis is based on an average of 15 and 5 stimulations per frequency and per mouse during SWS and REM sleep, respectively. Paired comparison between control conditions for SWS and REM sleep-to-wake transitions did not reveal any significant differences (P>0.05, two-tailed Student’s t-test). Latencies are represented as mean ± s.e.m. Asterisk, P<0.05; double asterisk, P<0.001; triple asterisk, P<0.0001 using a two-tailed Student’s t-test between mCherry control (red) and ChR2 animals (blue) for each frequency. d, Cumulative probability distribution of latencies from SWS to wakefulness after light stimulation (mCherry control, red curve; ChR2, blue curve). e, Cumulative probability distribution of latencies from REM sleep to wakefulness after light stimulation (mCherry control, red curve; ChR2, blue curve).