Figure 1.

Vigilant state scoring. (A) Configuration of recording electrode placement. Two burr holes were drilled asymmetrically at 2 mm anterior/1.5 mm lateral and 7 mm posterior/1.5 mm lateral to bregma. Stainless steel screws were placed in the holes and the EEG leads were wrapped around the screws. The screws and leads are secured with dental cement. Additionally, a second set of leads were implanted directly into the sternomastoid muscle approximately 1.0 mm apart and served to record nuchal EMG. (B) Top: Representative continuous recording of EEG and EMG. Bottom: Expanded view of a 5 s epoch from each state. The colored lines above the main trace indicate the specific epoch. From the acquired continuous EEG/EMG traces, vigilance states were first scored as wake, NREM sleep, or REM sleep using a custom program DJP. Next, experimenters blinded to the treatment groups confirmed the automated scores. (C) Double cross-over experimental design. OVX Sprague–Dawley rats (n = 11) were implanted with transmitters and randomized to one of two sleep conditions: AL sleep or SD. Once assigned to a sleep condition, animals were administered either oil vehicle or E2 according to our standard paradigm. At the end of the first recording period and 7 day washout period, the animals were crossed over to the other treatment but remained in the same sleep condition. At the end of the first cross over (and washout period), the animals were crossed to the other sleep conditions and treated as described above. Figures 2–5 represent the findings from this experimental design.