Plane Four is the fourth dimension across the multiverse. In it exists numerous different multiverses. All of the articles are about the Zero value of the fourth plane - the only place that is different across universes.
Exactly 0.000000001943578209465092851839265 inches from the Zero value exists the only plane we can know how to connect to, Neuronia. Neuronia contains numerous types of brain tissues, allowing whoever that can tap into it to preform numerous otherwise impossible feats, including but not limited to telekinesis, mind reading, and psionics. The Creators and The Chaos were unable to tap into this region.
There are numerous others. Most are empty, and are only used to attempt to psychically escape from the Chaos. Access to these are entirely unconscious and help lots with resistance.