Ellie Rotunno wrote: > There are two mechanisms > in sleep. The first is passive delta type--when neurons fatigue, nerve > impulses slow down and there is less excitability of the reticular > activating system. This is normal, deep, restless sleep, devoid of > emotional type dreams. Correction: This should say normal, deep, restful sleep. I hate being imperfect..:-) My best, Ellie