June 03, 2003
The dream weaver
By Carmelo Amalfi
GEORGE CHRISTOS dreams of getting back to sleep.

"I enjoy going to sleep knowing I will be taking part in this wonderful theatre in which I am the main star," he says.

The senior lecturer in mathematics and statistics at Curtin University of Technology in Bentley is discussing his latest creation - a book on the human brain, memory and power of dreams.

Dr Christos offers a new and insightful interpretation of why we dream and how memories are formed, stored and retrieved by the brain in Memory and Dreams: The Creative Human Mind, by Rutgers University Press.

Radical, but relevant to 21st century science, especially in the possible medical treatment of brain-related diseases and disorders such as Alzheimer's and dementia, Memory and Dream is written for the lay person - for dreamers like Dr Christos.

It explains how the human brain generates novel information and creative ideas using stored memories.

Dr Christos' interest in how the brain works began in the early 1990s after reading several books by leading researchers such as John Hopfield and Daniel Amit, who set out to map memories using mathematical models.

In 1991, while attending a Sydney conference on neural networks, he learnt of the theory by DNA co-discoverer Francis Crick that dreaming involved a process of reverse learning or unlearning in which the brain purged unwanted, spurious memories.

Others, including neuroscientist Jonathan Winson, suggest we relearn or rehearse memories and others believe we dream to forget memories, particularly bad or traumatic ones.

This led to Dr Christos' interest in REM, or rapid eye movement sleep, the phase of sleeping during which we dream, and lucid dreaming, in which the sleeper actually acts out a dream as if it were real.

In 1992, he was explaining to guests at a dinner party at his brother's home the subject of lucid dreaming and how American scientists found that sleepers held their breath when dreaming of swimming underwater.

"Someone at the party mentioned that a newborn baby, when thrown in the water, held its own breath," Dr Christos recalled. Something clicked.

It was at that moment that the Curtin mathematician saw what could be a link between dreams and a number of human diseases and disorders linked to the human brain such as SIDS, sudden infant death syndrome, dementia and Alzheimer's disease.

REM sleep was identified in 1953 in sleeping children, and later in adult patients who also expressed the same jerky side-to-side eye movements during dream sleep. Four years later, sleep researchers found we dream almost exclusively during REM sleep.

In humans, adults had about one to two hours of REM sleep while infants dream from five to eight hours a day. Studies with premature infants reveal that a fetus has even more REM sleep - possibly an entire day after the 13th week of gestation.

Cats and dogs dream. So do some birds.

What does a cat dream about?

"Chasing mice I suppose," suggests the mathematically minded genius with his back to the wall at his home in Bassendean.

We know cats dream, because their eyeballs also move during dreaming and from experiments in which that part of the brain involved in deactivating dream actions (to avoid hurting itself) were surgically destroyed.

Without the deactivating switch, the cat stalked and attacked invisible prey in the cage.

If all mammals have it, then REM sleep represents an important driving force in biological evolution. We have evolved to dream, Dr Christos says.

Weaker, older memories are discarded and the most recent and relevant stored for later use.

The progressive fading of older, irrelevant memories, except for those already written into our neural fabric (walking, talking and seeing), is crucial for survival.

The importance of REM sleep is further backed up by a phenomenon - REM rebound - identified in 1960. A person deprived of REM sleep on one night will have twice as much REM the next night. Continued REM sleep deprivation increases that rebound which can lead to physical and psychological problems.

During REM sleep, a small cluster of a few thousand neurons in the brain stem called REM-on cells get excited and stimulate most of the forebrain which includes the neocortex, thalamus and limbic system containing the hippocampus and amygdala.

It uses the same channels in the thalamus that our sensory inputs normally use when we are awake. Input into the brain during dream sleep is random or jumbled in content, which might explain why our dreams are so weird, yet real.

The confusion arises because during REM sleep, the brain processes the noisy input from the brain stem as if it were real sensory input.

"We are using the same apparatus to visualise dreams as we do when we visualise reality," Dr Christos explains.

He says we are frequently deluded during our dreams. How many times have you tried to flee from a foe or a pack of wolves, only to find yourself crawling on the floor, going nowhere.

"This sensation may arise from the fact that during dream sleep our motor actions are suppressed by the small group of neurons in the brain stem that inhibit the neocortex from sending messages to the legs to make them move," he says.

Can we smell and taste foods during dreaming? No. Since dreams involve mainly visual and auditory experiences, sensations like pain, touch and smell remain mostly inactive.

But the sound of a nearby alarm clock can blend into a dream.

During REM sleep, the eyes are controlled by a set of oculomotor neurons located in the brain stem. They are activated by the nearby excited REM-on cells.

Our eyes also tend to move with what we are "seeing" in a dream.

People who are blind from birth do not have rapid eye movements when they sleep. People who are blinded after birth still have rapid eye movements and experience some visual dreams.

Central to Dr Christos' book on the brain is that it does not need our help to perform the zillions of tasks that enable us to survive in a changing environment, day after day.

He says the brain can function autonomously, without our help.

So complex is it that it constantly generates new combinations or states of stored memories that form the neural template, basis, of our creativity.

"It is reprocessing your memories and generating new combinations," he explains. "What your brain does when you dream is very similar to what your brain does when you are awake.

"For example, when you are lost in the suburbs you use stored memories to find your way out. There is no real big difference between dreaming and being awake.

"The only difference is memories in a dream state just fade away."

Dr Christos says our memories are distributed across the brain, flashbacks of our childhood and adult life overlapping each other.

This multi-level storage of memory allows the brain to generate its own set or recombinations of our past experiences, called spurious memories.

Dr Christos says spurious memories - first identified in 1983 - were thought to be useless because there are so many of them.

The more we store, the more the neural network becomes bogged down in trash which has to be emptied. Failure to do so leads to memory overload.

Dr Christos says the human brain generates spurious memories by combining bits and pieces of already stored memories. It is spurious memories, or their recombinations, that represent the basis for creativity - and our survival.

Without them, we would just recall and relearn what we already know - just like a computer. Spurious memories are the key to being human.

"I believe we are almost like robots, not like robots since they act out programs. Brains generate instructions based on its previous experiences," Dr Christos said.

"I believe people could use their brains more by simply thinking, learning. But most people don't like learning. It takes effort and brain power. It is easier to copy."

Working on his literary creation nearly 20 hours a day, Dr Christos discovered reading and writing actually led him into different and complex branches of new thinking, creation, which enabled him to finish it.

"It drives me crazy sometimes," he says. "The more one knows, the more thoughts and ideas one generates."

Dr Christos says our memories and recollection of past events change with time. A lot of what we take in, such as how many cups of coffee you had on a particular day, is discarded as trivial and no longer useful. They are pruned.

During dream sleep, the trash (those weak memories) are dumped to save more important, new memories.

If the trash begins to pile up, problems begin to surface - such as schizophrenia (false associations) or dementia and Alzheimer's disease (inability to recall recently stored memories).

"Schizophrenia is characterised by false associations between memories, or disjointed personalities," he explains.

"Spurious memories fit the bill quite well, as they correspond to associations between memories.

"In the case of Alzheimer's disease, spurious memories can interfere with the retrieval of stored memories. It is often said that there is a fine line between genius and madness, and spurious memories provide a nice connection between these two states of mind."

Dr Christos says we dream to process, relearn recently acquired memories while deleting unimportant bits of those memories. By organising our memories, we are more predisposed to learning without hindrance.

But memories are robust, he says. This is because they are retrieved or recalled from not one but many neurons which act collectively.

Dr Christos says if a memory is stored in one neuron, it would be lost forever if that neuron was damaged.

But not in a collective in which thousands of neurons involved in activating memories can continue to function if other neurons in the network fail.

He says this connectivity extends to different parts of the brain where memory is represented.

For example, remember the lady in red who walked by as you boarded the bus home?

Her physical features are stored in the visual cortex, any emotional aspect such as love or fear is stored in the amygdala and other parts of the cerebral cortex and her name stored at brain sites dealing with language and speech.

Much of this resurfaces almost simultaneously when the memory comes to mind.

By making associations between memories, we build foundations for associated memories - two or more different memories that are recalled together.

Associations provide extra cues (or clues) to recall a stored memory.

"I don't think there is a limit to how much the brain can generate," Dr Christos says. "The number of different states the brain can store and generate is huge. And the more you use, the better it gets."

Dr Christos says memory recall and learning take place simultaneously.

"New memories stored in the network become part of the machinery that processes future input," he writes. "Memory and learning are complementary processes."

Learning - the way we perceive the world in time and space - depends on your memory bank.

"Nothing comes completely out of the blue, as it were," Dr Christos writes.

"When we seek a solution to a particular problem, we generally use various ideas, facts and memories to arrive at a solution that uses and satisfies most of the facts and constraints simultaneously."

So the more we know, the more spurious memories we generate and store during the learning process. But there is a limit. We can discover only as much as the brain is capable of comprehending.

Born in Perth, Dr Christos got an early start in science. By age 13, he had set up his first chemistry laboratory, completed a bachelor of science at the University of WA, studied quantum field theory and elementary particle physics at Oxford University and worked under Nobel laureate Abdus Salam in Trieste, Italy. In 1985, he returned to Perth.

Unemployed for three months, his first job outside his chosen field was as a Curtin computer programmer.

After two years, he joined UWA's physics department before returning to the mathematics department at Curtin where he now pursues research interests including neural networks.

Dr Christos says the brain is amazingly creative. It has the ability to generate memory states not intentionally stored in the brain. It can generate something new.

He says that creative states are generated naturally in a neural network system of overlapping, interacting memories stored over wide areas of the brain.

This overlap enables the brain to determine whether a spurious memory is useful enough to be stored.

"We often imagine that creativity is totally new and original, but in most cases it is not," he says. "It generally possesses features of known facts or stored memories."

Dr Christos says ideas are built on other ideas, on accumulated knowledge.

" ... no person is truly and absolutely original. Creative ideas are copied, borrowed and manipulated versions of what we know and acquire."

He says creative ideas are shared experiences needed to drive the copying system.

"All creative artists and scientists are invariably influenced by others, and although their ideas are often referred to as original, one can usually find traits from other artists and scientists in their work," he writes.

"Our ideas come from what we know, which mostly comes from others.

"What we do is combine this knowledge in unusual ways to generate something new."


If spurious memories are the source of human creativity, how do we tap into them to paint masterpieces or write bestsellers? Dream more, Dr Christos says. If dreaming involves the excitation of many spurious memories, it could be a good source of creativity.

Many artists and scientists try to use their dreams as a source of inspiration, new ideas.

"I know of one prominent mathematical physicists who keeps a pad next to his bed just in case he awakes from his dreams with a good idea," he writes.

In fact, a number of major discoveries have been made during dreaming, including daydreaming.

"Otto Loewi conceived how neurotransmitters work while dreaming over the course of two nights, Dmitry Mendeleyev awoke from a dream and wrote down the periodic table of the chemical elements and Friedrich Kekule thought of benzene rings during a daydream (in which six snakes joined in a stable ring of carbon atoms)."

Albert Einstein dreamed about relativity when he was a boy, imagining himself on a sleigh travelling faster and faster, approaching the speed of light.

Elias Howe, inventor of the sewing machine, dreamed of being surrounded by natives about to burn him at the stake when he noticed one holding an unusual spear with a small hole in its head.

But Dr Christos says the problem with using dreams as a source of new ideas is that they are usually forgotten as soon as we awake.

This is thought to be due either to a different neurotransmitter which takes over when we awake or the brain simply switching from an unlearning to a learning mode.

Dream recall is best achieved as soon as we awake and involves rehearsing backwards what happened in the dream. So have a piece of paper and pen handy when you return to reality.

Dr Christos says dreams are as positive or negative as a sleeper is: "It's a lot more emotional during dreaming.

"The neurons that stimulate the neocortex to generate dreams also stimulate the middle of the brain, called the amygdala, where emotions are stored.

"That's part of the reason why we wake from a dream crying, sweating or shaking."

As for people dying if they did not wake up before they died in their dream, it's an urban myth, he says. However, he concedes the possibility of a dreamer with a heart problem not making it out alive during a lucid REM romp in a virtual Paris brothel.

The last part of the book deals with a controversial possible link between dreams and SIDS, Alzheimer's disease and other disorders associated with sleep.

Having developed a possible link several years ago, Dr Christos suggests that infants, in the months after birth, can stop breathing by dreaming of being back in the womb where oxygen is supplied by the mother.

In other words, SIDS may have no physical cause. The cause may be in the mind of an infant.

"My hypothesis is that an infant, in the course of dreaming about its life in the womb, may stop breathing and subsequently die," he says.

Dr Christos says an infant's neural network needs to be wired up properly for it to detect and react to a sudden lack of oxygen or excess of carbon dioxide.

"It is unlikely that these mechanisms would be fully developed in a newborn since they were not required in utero, nor can they be properly tested or developed until the infant is born," he says.

SIDS is the second most common killer of infants in the first year of life. He believes the risk of death can be avoided by avoiding having a sleeping infant in a fetal position and covering them in excessive clothing.

  • Dr Christos will be signing copies of his book at New Edition bookshop next Saturday. Cost $50. Recommended retail price in Australia is $72. More information about Dr Christos' Memory and Dreams at www.maths.curtin.edu.au/christos

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