Trans. The sleep state is one of the manifestations of trance, the third state (besides sleep and wakefulness), in which we are constantly. The trance is well described by the example "I was thinking ..." In fact, this is a narrowed field of perception, when we focus on some thoughts, or some kind of activity. When I operated, I did it in a trance - that is, I was absorbed only in what was at my fingertips, and did not think about the family evening. Meditation, hanging on social networks or computer games, prayer, dissolving in music, a combination of total concentration and relaxation at the same time in combat sports and other competitions ("combat trance") - and you have obviously learned to catch and use a natural trance in the state of sleep .
Perhaps we are talking about lucid dreams - a state between the phase of REM sleep and wakefulness, when a person is aware of his dream and can control it. In addition, as a kind of lucid dream, you can imagine "sleep paralysis" or "sleep stupor", but this is not the most conducive to thinking state ...)
Sandman. And in English the word "dream" means "dream". I think it is somehow interconnected. How wonderful it is to dream of something great, dozing on the couch in the early hours of the morning!