“Dreams are maps.” (Carl Sagan)
Dreams have puzzled, terrified and inspired our species for thousands and perhaps millions of years. Over the eons, we have speculated that dreams were sent from the gods, from dead ancestors or were out of body journeys made entirely by the mind. But dreams come from our own brains to try and make order on a chaotic world. Tibetan Buddhism even teaches that dreams are rehearsals for what happens to the mind after death.
Dreams do stimulate certain nerves and muscles, especially the flight and fight response and stimulation of the sexual organs. Perhaps the brain is exercising the nerves and responses needed to one day perform the important activities of flight, fighting or fornicating. Anecdotal evidence suggests that celibate people dream about sex more often than sexually active people, but there have not been any reliable studies to prove this.
Where Are Images Coming From?
Although our bodies need the down time in order to recharge, the brain never sleeps. It keeps on generating complex signals which may help us to prepare for future events or even to forget some events. However, not all of the brain is active. According to Harvard Medical School’s Robert Stickgold, the hippocampus gets some rest. The hippocampus is thought to be a primary player in helping long-term memory.
One of the theories about dreams is that it helps us to remember. But the hippocampus, the very organ needed for long-term memory, seems to be slumbering along with the body. It does not seem to play much of a role in dream making. Robert Stickgold theorizes that dreams are sent to the dreamer from the neocortex.
The neocortex is also used in memory, but not long-term memory. Its specialty is seismic memory, which is what is able to process abstract concepts rather than actual memories. Because it is not directly liked with what we have learned from life with long-term memories, the images in dreams wind up being very bizarre and abstract.
What’s the Advantage in This?
Besides making dreams very entertaining and bizarre, what could be the point of having the neocortex handle this responsibility rather than the hippocampus? Francis Crick and Graeme Mitchinson postulated in 1983 that the neocortex as best able to keep the brain’s memory and functioning strong by removing memories or even neural pathways unnecessary for survival. This could explain recurring dreams, in order to help desensitize the person to the events in the dream.
Stickgold takes this a step further. He had volunteers play the video game Tetris for hours and then see how log it take for them to dream about Tetris. In order for the brain to process Tetris, it needs to learn Tetris without being distracted by such things as logic or long-term memories. Only abstract concepts like touch, putting together puzzle pieces and colors need to be involved.
Only after going through the neocortex can it then is gradually placed into long-term memory and into everyday life. After years, maybe, Tetris in itself becomes an abstract concept able to help explain new information a person encounters in daily life.
References:
“The Function of Dream Sleep.” Francis Crick & Graeme Mitchinson. Nature Vol. 304 No. 14 July, 1983. http://profiles.nlm.nih.gov/SC/B/C/D/K/_/scbcdk.pdf
MSNBC: “How the Brain Turns Reality Into Dreams.” http://msnbc.msn.com/id/3077505/
“Sleeping, Dreaming and Dying: An Exploration of Consciousness with the Dalai Lama.” Francisco J. Varela, Ph.D. Wisdom Publications; 2002.
