Autonomous process kept away from your conscious control (for most cases) to sharpen your memory, living out expectations/desires/fears wich otherwise would make it impossible for your mind to cope up with energies.This acts as a psychological therapy to prepare your mind as ‘blank slate’ again recording previous days most emotional and troublesome scenes within mind game. This state was also designed to carry important messages from realm of knowledge to guide and support your earthly endeavour, if you listen. Dreams are biological in nature with neurons fired to create the scenes, memory writing, responses etc. But this is secondary – for first they are created in causal plane to be played out in astral plane unlike other scenes which are written for your 3D physical plane.
Astral plane provides a unique personal flexible ‘universe’ where you can create temporary sets, characters, story line etc. to teach or release stress or provide hints or just have fun. Remember that like the physical world being a multiverse, the astral world is also a multiverse where you can play within the ‘local theatre’ that you create as well as roam around in ‘general creations’ created by group consciousness or higher dimensions created by evolved souls as learning centers…
The dreams are also multidimensional in nature – starting from non-local causal plane to very specific bio-chemical activity in brain as well as several organs of body taking part in living out the experience. The process is exactly same as ‘Earth Dream’ or 3D world physical dream. .. which is bit more fixed, general world and takes much more efforts and focus to customize it to suit your needs!
Sleep is good if you have total control over it… so I emphasize again and again to take back conscious control of your sub-conscious realm, your dream state, deep sleep state and Turiya state to become a complete man!