As spirits seem dissociated from the body, being able to leave during an Out-Of-Body, and can ignore physical barriers, how then does the spirit communicate to the biochemical arrangement that is the mind? What is the point of connection? The spirit does not need to switch densities, so the mind/spirit connection is not vibrational, being on the same wave length as you say. As the spirit can function without a body the connection is not biochemical. As spirits develop during incarnations in life forms on diverse worlds wholly incompatible with each other the connection does not appear to have a physical requirement.
This puzzle is most easily understood if one considers how sub-atomic particles operate. However diverse the various elements of the physical world seem, they break down into the same component parts. The base building blocks are the same. Spirits are composed of a substance that is physical in the larger scheme, and surpasses in its reach any one density vibration. Just as on the sub-atomic level you consider some elements to communicate electrically, encouraging or inciting an electron flow, and other elements to be inert, just so your spirit considers your mind to be capable of an interchange where the stone walls it passes through are inert. The spirit communicates to the mind by biochemical means, by inciting biochemical activity. It does so by adjusting itself to the density of the incarnated body and to the peculiar biochemistry of the life form. This feat is no more spectacular than tuning an x-ray machine to penetrate the thickness of an object. During each incarnation the spirit quickly familiarizes itself with its new physical body, and gets down to business.
Does the spirit have memory, as the mind does? Most certainly, and remembers the lessons learned during each incarnation flawlessly. Humans are used to their conscious memory being capable of distortion, of remembering incidences as they wish, not as they were. The spirit, however, is like the subconscious and does not distort memories. How is it then that the babe, incarnated by an old and wise spirit, does not remember its past lives? The spirit can only speak to the mind as the mind is ready to receive. If the biochemical pathways for the concept the spirit wishes to relay are not yet in place in the mind, the spirit can only speak to the emotions. Thus humans feel they have lived before, but do not have an explanation for the concept. Thus humans may sense that an incident is similar to another experienced before in a past life, but unless they are willing to entertain the concept of past lives, they will not be open to having these spiritual memories unfold.