The human brain is a physical lump of matter that is part of your material body. When the body dies, so does the brain. To avoid the futility of trying to reach out to the Astral or Celestial planes directly from your brain-box, try attuning firstly with that part of yourself that is not made of matter. It is kind of like the old-fashioned way of going through the operator when placing your telephone call.
Some question why, if reincarnation is real, they cannot recall past lives. That is because they are relying on their physical brain, which only stores memories of this life. Those who train themselves to access the higher part of their being can then move on to access the higher realms, including what I call Inter-Dimensional (ID) worlds.
While we become increasingly fascinated by technology, including AI and Trans-humanism, the tried and true methods of meditation and prayer are (at least for now) still the best way to reconnect with your Overself - and, from there, to the Stars.
Credit for Image Above: https://www.youtube.com/watch?v=HWEaOdk5B5E