The Happiness of Deep Sleep Is Due to Serotonin?

Every day we have waking dreaming and deep sleepin. It's not every day that you get hit on the head with a club, thank god. And it's not every days that we have mystical visions. So these are common experiences, and they are used in vedanta bi to point out the one consciousness behind waking dreaming anddeep sleep. But is it that the happiness of deep sleep is due to seratonin or something like that? You are mixing up two things. Why only deep sleep? In that case, the happiness you get from having a ukuki in waking state, that also. Is it due to er, the bliss of brahman? Or is it due