This book was simultaneously written for a general audience and for the scientific mind.  It is basically a popular science book, but contains ideas I have developed over the last 10 years. 

 

Here is what I believe the book offers.

 

1. It explains in terms of the components of the brain (namely neurons, synapses and neural networks) how memory is stored, retrieved and processed in the brain, and why neural memory is so different to computer memory.  I also discuss how the brain develops after birth, and why I believe that the brain does indeed forget.  I am amused that some psychologists are only recently starting to think that the brain does not keep a trace of every experience.  [See recent issues of New Scientist.]  Neural network models suggest that memories are constantly competing with each other, they change with time and some memories are simply displaced.  Memories are also lost as neurotransmitter stores (where memory is actually stored) decay with time.

 

2. It explains how the brain generates new ideas and creativity.  In the brain, memories are stored in a distributed and overlapping fashion, sharing neurons and synapses, quite unlike the way memory is stored in a computer.  A consequence of this common storage arrangement is that the brain generates its own 'memory' states, called 'spurious memories'.  These states have been observed in mathematical models and there is every reason that they should also be present in the brain.  Spurious memories are generally comprised of combinations of features of stored memories.  I have suggested that these spurious memories are the basis of creativity, and that they allow us to adapt to an ever-changing environment.  Spurious memories are actually also necessary for new learning.  This is a major shift to previous thinking, as most researchers were interested in finding ways to eliminate them from neural systems (hence their name) to improve the retrieval of stored memory, but the brain is not just a recording device.  I am saying that spurious memories may be the most important brain states, as they enable the brain to function autonomously, to adapt, to be creative, and to learn. Albert Einstein once said, "imagination is more important than knowledge".  That may be true, but if I am correct this should be supplemented with the fact that imagination is based on knowledge.  This is because new ideas (spurious memories) are based on known information or memories.  You would hardly get an idea about quantum field theory if you knew nothing about it, and in any case it would not mean much if you knew nothing about it.

 

3. It explains how the brain functions autonomously, without any need for central control.  This is achieved by learning spurious memories. Without them the brain would only be able to recall what was stored in it. Neural network researchers normally store memories in neural systems by adjusting the links between neurons by hand, but there is no one that does this in the brain.  The brain accomplishes this by itself and to my mind spurious memories are the way it does it.  This is interesting because it means that whatever you learn is in a sense already stored in your brain.  When you come to learn something new, a weak spurious memory (that already exists in your brain) is entrenched so as to become a strong stored memory.  This idea has serious implications for building real artificial intelligence systems.  Most AI researchers are still looking at models with a central controller. In my model there is no need for central control. 

 

4. It explores what the brain may be doing during rapid-eye-movement (REM) sleep, the phase of sleep normally associated with dreaming, incorporating all the neurobiological evidence (such as what exactly is going on in the brain when we dream).  I also address the function of dream sleep and why it is that we and all other mammals have evolved to dream.  The function of dreaming is one of the main unsolved puzzles in systems neurobiology.  My theory on the function of dream sleep is based on an idea first put forward by Nobel Laureate Francis Crick (DNA) and Graeme Mitchison, but with a twist.  They suggested that we unlearn or reverse-learn when we dream.  A consequence of this is that we forget unwanted memories and reduce obsession by dreaming.  I agrees with that, but Crick and Mitchison also suggested that we dream to reduce parasitic or spurious memories.  I have found however (by simulation experiments on neurobiologically realistic neural networks) that reverse-learning actually increases the proportion of spurious memories.  This is great news for my theory that spurious memories are important.  My theory is that we dream to generate roughness (spurious memories) in our memory space so we are better disposed to learn and be more adaptive in a new and ever-changing environment.  Dreaming also aids creativity.  Without enough REM sleep our learning capacity is diminished, we are unable to think, adapt and be creative.  In addition to the above, I also review ALL other theories on the function of REM/dream sleep, and explain for example why Freud had it all wrong.  Freud was not aware for example that babies and children have so much more REM sleep than adults.  What psychological need could an infant have for so much dream sleep?

 

5. It presents my theory on the cause (and trigger!) of sudden infant death syndrome.  I assert that my theory is the only theory that fits in with all of the known facts about SIDS.  Basically, the theory goes along the following lines.  Lucid dream research has shown that we try to act out our dreams, as much as is possible.  When a researcher dreamt that he was swimming underwater, he really held his breath while he was asleep.  We also dream about our own personal memories.  Adults dream for about 2 hours each night, whereas a baby can dream for up to 8 hours a day, but what could a little baby be dreaming about?  What memories can it possibly have?  I suggest that it could dream of being back in the womb where it did not have to breathe, because the mother supplied it oxygen through the blood, and just as the researcher held his breath while dreaming he was swimming underwater, the baby may stop breathing.  This theory explains why all the neurological alarms are not activated and why there are no physical signs of death (no struggle).  Remember that a SIDS death is only diagnosed after every other cause of death is excluded.  The first and only symptom of SIDS is death.  Note, I am also saying that the reason why medical researcher have not made an advances in understanding SIDS is because it is in the mind of the infant.  My theory explains all sorts of things, such as why the risk is higher in the prone position, why it is more prevalent in colder climates, why dummy (pacifier) sucking helps but thumb-sucking is a risk, etc.  I also suggest how the incidence of SIDS can be reduced further by making the environment of the sleeping infant less womb-like.  This aspect of the book was recently reviewed in New Scientist (12 April 2003).  See http://www.newscientist.com/opinion/opbooks.jsp?id=ns23903.

 

6. Among many other things, I have even come up with an explanation of déjà vu, based on the confusion of spurious memories with real memories.  Normally the brain takes much longer to converge to spurious memories (as observed in neural network models).  Déjà vu results when for some reason the brain converges to a spurious memory quickly giving us the impression that we know that 'memory', whereas it has not been formally learnt as yet, and is unknown to us.