The objective of the threshold, or mountaintop, experience, was a medicine vision of benefit to the people as a whole. Without food, water, companionship, shelter, or defenses against predators, sometimes in great pain from self-inflicted wounds, the body longed for spiritual answers. The sacred ancestors sent dreams to console and inspire, and the Great Spirit provided "allies" or "helpers." When the initiates returned from this time with the Great Creator and the sacred ancestors, they were considered to have confirmed visionary intent. If the intent were not confirmed, the candidates would often return again–and again– until signs from nature indicated that the quest had been consummated. Thus, the community was blessed by the spiritual growth of its members, and every vision took its place in the legendary annals of the people.

http://plainshumanities.unl.edu/encyclopedia/doc/egp.rel.051