What are currently recognized as dreaming periods are the REM (rapid eye movement) portions of sleep. What is generally not known however is that we dream and have other experiences at deeper levels of the psyche that aren’t usually fully consciously remembered. Some of these are formless or imageless interactions. The information and experiences we have on these levels is translated into dream imagery at levels closer to our waking consciousness, and this is what is recognized as REM dreaming.
In other words, we still dream in non-REM periods, but these dreams are trickier to remember directly the deeper we go, because there the information we receive is usually too vast for our conscious minds to contain. So we translate it in symbolic form through the image-laden medium of REM dreams. And yet, as we stretch our dreaming attention and conscious capacity, we are more likely to remember more information from these levels, which is more akin to a direct knowing.
The confusion that REM periods and dreaming periods are exactly synonymous is one that has come about through the scientific study of dreaming from outside observation. But by recognizing that REM is associated with the scanning of dream imagery, it is easier to see that those non-REM periods of sleep are not necessarily ones of ‘unconsciousness’ but quite the opposite, they are periods of superconscious activity that escape our conscious focus, imageless ‘dreams’ of a magnitude that is mind-blowing to glimpse!