Polysomnography

Anesthetize the animals (ketamine and xylazine,100/10 mg/kg. i.p.) for polysomnography.

Screw 3 electrodes to skull above parietal and frontal cortex and cerebellum as the reference for electroencephalogram (EEG).

Slip 2 wire electrodes between neck muscles for electromyogram (EMG).

Braze thebleads to a miniature plug (Plastics One, Bilaney, Germany), cemented to skull using acrylic cement (Superbond, C&B Sun Medical) and coated using dental cement (Paladur,Heraeus Kulzer).

For pain caring, administer a subcutaneous injection of carprofen (5 mg/kg).

Once recovered, house mice in individual barrels under 12h light/dark cycle (light-on 7 a.m.) and constant temperature, tethered to the acquisition system and record 1 week out of 3 over 12 consecutive months until natural death.

Based on amplified/digitized unipolar EEG and bipolar EMG signals, visually score vigilance states using a 5s sliding window frame and assign them as Waking (W), Slow Wave Sleep (SWS) and Paradoxical Sleep (PS) to produce hypnograms and state quantifications (Sleepscore, Viewpoint).