Where is our Aatma or Soul when we sleep? What exactly happens to it? I tried finding answers, but could not get any answer from within! Help
In Buddhism there is not concept of Atman. But has the concept of Anatta, means you have not control over the aggregates or anything else to be considered as self, me or mine. Also there is no core which is unchanging or everlasting which you can consider Atman. It does not relate to the concepts given in your question.
I know that there is no concept of "soul" in Buddhism in general but in Tibetan Buddhism there are certain physical localizations of consciousness... which is the closest thing to an answer to the OP's idea of "soul" existent in Buddhism.
I read about this localization in the past in a Tibetan dream book its either in the head or heart which is why in Tibetan dream yoga one puts one hands over the heart as one sleeps..