I dream, therefore I am: Hypnagogia and the Brain

Ay me, for pity! what a dream was here!
Lysander, look how I do quake with fear
William Shakespeare
Midsummer Nights Dream, Act II, scene 2

Dreams are the answers to questions that we haven't yet figured out how to ask.
Fox Mulder, The X-Files

For centuries human beings have experienced the impossible through dreams. In particular, the murky boundary between sleep and waking known as sleep paralysis has allowed us to create in our minds the stuff of fairy tales. Drifting off to sleep one often experiences curious dreams of a nightmarish quality as well as highly unusual bodily sensations. Both during hypnagogia, the period of time just before sleep, and hypnopompia, a similar state just before waking, our minds create hideous hags and ghouls, terrible enitities, the experience of alien abductions, sensations of non-existent pain and the incomparable feeling of flight [1].
Beginning with Aristotle, philosophers and scientists throughout history have been fascinated by the half-dream, half-waking state of hypnagogia. In the third century A.D. the philosopher Iamblichus described the “voices and bright and tranquil light in the condition between sleeping and waking” which he attributed to a divine force. The lurid and eerie illustrations of alchemical manuscripts suggest that alchemists in the Middle Ages may have been inspired by hypnagogiac states during their distillations. In fact, many thinkers and artists including William Blake, Samuel Taylor Coleridge, Edgar Allen Poe, Havelock Ellis and Carl Jung were known to make use of the creativity induced by the trance-like state and sensations of hypnagogia[1].
The early 20th century Russian journalist and philosopher P.D. Ouspensky believed that by studying hypnagogia he could come closer to understanding the unconscious mind. Ouspensky studied what are called lucid dreams, a kind of hypnagogia during which the individual retains some awareness and control over his unconscious dream state. He discovered that during hypnagogia he was actually able to exert influence over dreams and alter them at will. Ouspensky famously stated that “we have dreams continuously, both in sleep and in waking state” a statement that was later to be proved true by the discovery that the brain’s neurons are as active during Rapid Eye Movement or REM stage of sleep as when a person is awake[1].
The phenomenon of Sleep-Paralysis occurs just after or before REM sleep the dreaming part of sleep when the brain’s neurons are as active as during waking hours. People reporting Sleep-Paralysis, are aware of the inability to move while drifting off to sleep or waking up. Quite often, the paralysis is accompanied by hypnagogic hallucinations. Possible physiological causes for Sleep-Paralysis may involve the post-synaptic inhibition of motor neurons in the pons region of the brain, possibly due to low levels of melatonin. This depolarization of motor neurons during REM sleep is in fact useful as it prevents people from physically doing what they are dreaming about [2].
Hypnagogic and Hypnopompic experiences can be classified into a three-factor model. The first factor, termed the Intruder factor is characterized by the sensation of fear accompanied by auditory and visual hallucinations that may originate with the hyper-vigilant state initiated by the midbrain. The second factor, Incubus, consists of the pain, pressure of the chest and possible difficulty breathing. Incubus is generally attributed to the hyperpolarization of motoneurons. Vestibular-Motor hallucinations, the final factor of hypnagogia is comprised of seemingly impossible experiences such as floating, flying, general feelings of euphoria and sometimes even sexual pleasure. While the first two factors are clearly associated with threat and assault the last is more autonomous. What is certain however is the link between the hypnagogic state and REM sleep [3], [4].
A study on the memories that create dreams called Replaying the Game: Hypnagogioc Images in Normals and Amnesiacs indicates that during hypnagogic sleep people do not actually dream about events stored in their declarative or episodic memories, the memories that allow one to process and retain newly learned information. The study compared the dreams of people with amnesia and control subjects who were both taught to play a computer game which involved arranging colored blocks. The study showed that people with amnesia, despite the damage to their hippocampus that prevented them from storing new information were able to dream about the images they had been exposed to in the game during their hypnagogic state although they could not actually remember playing it before they went to sleep. These results indicate that memory of the event is not necessary to dream. It is therefore possible to dream of things we have never experienced or known merely by using our semantic knowledge which involves general and abstract concepts [5].
What does all of this mean in terms of our understanding of the brain? Agent Fox Mulder may be a fictional character; nevertheless his statement about dreaming attests to his, or rather his creators’ perspicacity. Dreams may well be the answers to those essential questions that we cannot yet formulate. In his book The Natural Depth of Man, the psychologist William Van Dusen wrote “much of the hypnagogic area looks simply like cute images and odd sentences being tossed around one’s head until one asks precisely what the individual was thinking of at that same moment. Then it begins to look like either a representation of the person’s state or an answer to his query” [1].They are the answers to our deepest fears and our greatest pleasures. When we dream we are able to create creatures we have never seen or heard of, to experience sensations we have never done. Like phantom-pain and placebo effects, the dreams of people experiencing hypnagogia show that the brain is able to produce output with no external input, to truly create something. To me it is this ability to create that validates my perception of myself. Descartes wrote Cogito Ergo Sum, I think therefore I am. We know this to be in part false…lots of things are without any thought. However to me, the statement describes my own unique human experience: not just that I think and can process information like a computer or machine but that I can create and imagine things I have never seen before, if only in my dreams.

Works Cited
[1] www.forteantimes.com/articles/163_hypnagogia.shtml Waking Sleep
[2] http://en.wikipedia.org/wiki/Sleep_paralysis Sleep Paralysis symptoms and causes
[3] Cheyne et al. Hypnagogic and Hypnopompic Hallucinations during Sleep Paralysis: Neurological and Cultural Construction of the Night Mare Consciousness and Cognition, vol 8, 319-337, 1999. available at: http://portal.isiknowledge.com/portal.cgi?DestApp=WOS&Func=Frame&Init=Yes&SID=H21L3nli6D5BjCmBNea
[4] http://www.springerlink.com/content/n70183m218027533/ J. A. Cheyne, Sleep Paralysis and the Structure of Waking-Nightmare Hallucinations
[5] www.msnbc.msn.com/id/3077505/ How the Brain Turns Reality into Dreams, Kathleen Wren