Topic: ultradian sleep rhythm

The mammalian neuronal activity during sleep consists of two main states: non-rapid-eye-movement (NREM), also called slow-wave, and rapid-eye-movement (REM), also called active or paradoxical. The mechanisms underlying this ultradian sleep rhythm are not well understood but likely depend on reciprocal interactions between multiple populations of neurons in the brainstem. Studies have shown variability in sleep patterns across different species, complicating the identification of common mechanistic principles [Siegel, 2008]. Recent evidence in non-mammalian amniotes suggests that similar sleep