Figure 2.

The responsivity of the sleep/wake circuitry to the modulatory effects of gonadal steroids is developmentally organized. A, Gonadal steroid replacement and analysis paradigm-within animal design. The order for EB or TP replacement was randomized to control for the order of exposure. B, E2-mediated suppression of REM sleep was dependent on brain organization. E2 significantly reduced REM sleep in females only. Similarly, T also suppressed REM sleep in females only. *, P < .05 vs oil. C, The magnitude of REM sleep suppression by E2 is significantly different based on brain organization. There is a significant difference between females and males. There are no differences between T's effects on REM sleep. *, P < .05 vs females. Data are represented as mean ± SEM.