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Posts Tagged ‘Dreams’

Dreams, Another Exercise in Things we Don’t Know

Posted by Jenna Capyk on October 25, 2011

When it comes to sleep and dreams a few things are clear. Firstly, people really like to study them. Secondly, some of the gross physiological features of sleep can be observed and measured. Thirdly, despite all of this research, there is plenty of contraversy in the field of sleep research. Scientifically it’s a fascinating topic involving an altered physical and mental state that is somewhat independent of the conscious mind. It also seems to be another one of those ubiquitous phenomena in the human experience that we have trouble really putting our fingers on.

Before we talk about the things we know about sleep, lets talk about how we know them. The gold standard for measuring sleep phenomena is polysomnography. This technique measures three things. It encorporates an electromyogram (EMG), which is a measure muscle tone; an electro-oculogram (EOG), which is a measure of eye movement; and an electroencephalogram which is a measure of brain activity. In addition to these three measurements making up the polysomnograph, researchers often use direct observation to monitor gross muscle movements, or sensors that measure chest wall movements, leg movements, or oxygen saturation of lung and other tissues. Body temperature is also sometimes measured.

Like I said earlier, there are several basic things that we know about sleep. For example, there are two main kinds of sleep: rapid eye movement or REM sleep and non-REM sleep. Non-REM (N-REM sleep) can be further broken down into four stages and these are all defined by measurements of the polysomnophraph. First, if you’re drowsy but not asleep you have low voltage alpha waves on your EEG reading. Stage 1 N-REM sleep is characterized by low voltage theta waves and slow, asynchronous eye movements. This is the only stage of N-REM sleep in which your eyes are observed to move, and it is also the only stage of sleep during which you may not perceive yourself as having been sleeping upon waking. Stage 2 N-REM sleep is characterized by “sleep spindle” patterns and “k-complexes” in the EEG. “Sleep spindles”
are 1.5 sec long 12-14 Hz EEG waves that are generated when groups of nerves in your thalamus become synchronized by a pacemaker mechanism. I find this really cool because it reminds me of synchronization of your heart nerves and muscles by a similar internal pacemaker. It creates a regular rhythm by having the nerves work together. Stage three and four N-REM sleep show very slow delta waves. This is called deep sleep or slow wave sleep and stage four is basically just deeper than stage three.

In all of these stages of N-REM sleep the EEG, measuring brain activity, shows very different patterns than in wakefulness. These patterns tend to be both synchronized and rhythmic. In REM sleep, however, we see low voltage, high frequency waves that are similar to relaxed wakefulness. REM sleep is defined by the presence of this activated and desynchronized EEG pattern, rapid eye movements, and very low muscle tone. REM sleep also has two phases: tonic which is continuous and has the typical EEG pattern and muscle atonia; and phasic which is intermittent and involves the bursts of eye movement and irregular breathing and heart rate. About 80% of all dreaming happens during REM sleep although the two states are more loosely associated than previously thought.

As you fall asleep you pass through the stages of N-REM sleep in order and then into REM sleep after about 90 minutes. These cycles then repeat 4-7 times throughout the night with stage 3 and 4 N-REM sleep making up the largest proportion of normal sleep time and the transitional stage 1 N-REM making up the smallest. You spend about 20-25% of the night in REM sleep, although this number is larger for small children. Each stage involves less muscle tension than the one before and in all stages but phasic REM sleep the parasympathetic autonomic nervous system dominates.

The biological function of sleep itself is still under debate. We know that during N-REM sleep the body temperature is controlled at a lower set-point whereas in REM sleep temperature regulation ceases altogether. These effects have prompted the theory that sleep is important for the mechanisms of body temperature control. Another theory is that it is crucial for consolidation and maintenance of memory. This has been one of the most prevalent theories for a long time, however there is much contradictory evidence. Another theory is that it is necessary for general rejuvenation and neural growth. This theory is supported by the fact that REM sleep is crucial for CNS development in young animals, and the rather obvious observation that when you wake up you feel better than when you’re tired. Similarly, there are parts of the brain that actually undergo growth of new neurons throughout life, and sleep deprivation (specifically REM sleep deprivation) slows this neural growth.

If our understanding of the reasons behind sleep is sketchy, it’s nothing to the sketchiness surrounding our basic understanding of dreams. As I mentioned, dreaming has been closely associated with REM sleep, and this sleep stage is also poorly understood in terms of its biological role. While the other stages of sleep, as I was saying, can be explained as having a regenerative role on the body and mind, there is no obvious adaptive role for REM sleep. That is it’s hard to see what selective pressures would have resulted in this sleep stage developing through evolution.

People (at least adult people) can basically do without REM sleep. There are several pharmaceuticals in wide use that suppress REM sleep and people on these drugs undergo a massive reduction of REM sleep, basically to the point of eliminating this phase. These people do not suffer mental collapse, however, and seem to undergo no ill effects. In fact, some studies suggest that they show improvements in memory. Similarly, some people lose the ability to have REM sleep because of a brain injury and these people seem just fine too.

REM sleep is not just a human trait, however. All land animals and possibly all birds have REM sleep cycles, although of course we can’t ask the animals if they are experiencing what we consider dreams. Dreaming isn’t actually a necessary component of REM sleep in humans. Injury to a relatively small cortical region in humans eliminates the ability to dream while retaining REM sleep cycles. Some people also report never dreaming, although they also experience REM sleep. Small children experience a lot more REM sleep than adults, but they also report fewer dreaming experiences.

At one time, neurologists tried to explain dreaming as spontaneous and random neural signals originating from the part of the brain that generates REM sleep; This theory posited that dreams were basically a byproduct of REM sleep generation. A systematic investigation of dreams, however, showed that although they can be strange, they are definitely ordered and non-random and incorporate many components of waking life. This seems to suggest that they may have a role of their own rather than simply being a product of a different process.

To be honest, when I started researching dream science I expected to find a bit more scientific consensus on the subject. It does seem, however that the jury is basically out on everything from the specific role of sleep in general, to the reason we have REM sleep, to how closely connected REM sleep is to dreaming, and why we dream. I guess it’s not that surprising that dreams are hard to research when you consider them as an experiential rather than empirically measure-able phenomenon. The human mind, and the underlying neurological circuitry, is really a beautiful and complex thing. It’s a bit ironic that one of the hardest things to wrap our minds around is, in fact, our minds.

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What Dreams Have Come: A History of Dream Interpretation

Posted by Ethan Clow on October 21, 2011

Last Tuesday we talked about dreams on Radio Freethinker. Where do they come from? What do they mean? Why do we have them? These are all questions that have been around for a long time so I assumed there must be a sizable amount of literature throughout history of people trying to answer them.

Well, not really.

I was actually more than surprised by the lack of good scholarly resources on dreams and dreaming. Every time I put dreams into Google, I got a bunch of pseudoscience dream guides and other dream woo. Even when I used Wikipedia, and I don’t normally use it as a primary source but I was getting desperate, anyway – using Wikipedia was proving just as difficult. None of the articles had satisfactory footnotes or references. Some of the statements had no reference at all, or worse, some dream woo reference.

Dream Caused by the Flight of a Bee Around a Pomegranate a Second Before Awakening by Dali

Fortunately I was able to find a few reliable sources and had a couple books that I could turn to. Truly, someone needs to write a collective history of dream interpretation from a skeptical point of view.

And now let’s look at my history of dream interpretation from a skeptical point of view.

It’s likely that dream interpretation has been going on since humans were capable of interpretation but one of the earliest (if not the earliest) is from ancient Sumer in the epic poem Gilgamesh – the hero Gilgamesh dreams of an axe falling from the sky, his mother interprets the dream as a prophecy,  but not a literal one, rather the dream tells the future through its symbolism.

This view that dreams represent the future, either in the forms of prophesies, omens, or in some cases, were literally happening, often through some sort of spiritual or divine process, would remain very constant throughout recorded history.

In ancient Babylon dreams were viewed as messages from the gods. Bad dreams were believed to be sent by demons whereas pleasant dreams were divine.  This is interesting since it actually differentiates between what type of dream someone has. For example, if you have a particularly wacky dream, even if you’re creative, it’s hard to figure out how that’s an allegory about the future. However, by assuming the dreams are sent, you explain why you might have very good dreams, very bad dreams or dreams you can’t understand or comprehend.

Cultures all across the Mediterranean all seemed to share similar beliefs regarding dreams as messages from the gods. In addition many also believed that dreaming was a way to contact the gods. For example, if you were ill and wanted the help of the gods, you would often visit a temple and sleep there in the hope that the god would visit you. You would report your dream to the priest and he would interpret it for you and prescribe a treatment. (My guess is whatever you dreamed would be interpreted as some contact with the gods)

This process was often called incubation and usually took place in the temples of dream gods of their respective culture.

In ancient Greece, ideas about dreams were adapted from other cultures like Babylon or Egypt. Many believed that dreams were sent by the gods and that they contained prophesies of the future or bits of wisdom that needed to be interpreted. This would frequently happen in a temple of a dream god.

Various Greek philosophers such as Democritus and others argued that dreams were evidence of the divine and that dreams allowed for the communication of some form between gods and humans. However we start to see a bit of a shift in that thinking with a number of Greek philosophers like Plato, Aristotle and Pythagoras.

Especially Plate who seemed to argue that dreams were the soul being detached from reason and rationality. When you sleep, the governing part of the soul is dormant and the wild crazy soul is active, often spurred on by intoxicating drinks and food.

He still believes that dreams have a divine component but mostly only for the wise folk who feed their soul good food and philosophy and achieve harmony and all that good stuff.

Aristotle seemed to believe that dreams were not divine or at least, not supernatural. However he didn’t seem to have a clear idea what they were.  (Doubt: A history, page 23)

to quote Aristotle: “For, in addition to its further unreasonableness, it is absurd to combine the idea that the sender of such dreams should be God with the fact that those to whom he sends them are not the best and wisest, but merely commonplace persons” – On Prophesying by Dreams

Over the centuries the debate seems to go back in forth between the two ideas, one that dreams are divine (either communication from the gods or divine in other ways) and that dreams act as either prophesy or omens. The conflicting idea, presented by Plate and Aristotle and taken up by people like Cicero in Roman times that dreams are not (necessarily) divine but rather have more to do with what the individual does (both physically and spiritually) and these actions cause the dreams.

In early Christian writing it’s very clear that dreams are messages from God. In fact, the conversion of the Roman Empire to Christianity was because of a dream Constantine had.

This view on dreams in Christianity seems to be supported by church founders and philosophers like Augustus and Aquinas. (Dreams in myth, medicine, and movies By Sharon Packer pg 99-101)

This view seems to change quite a bit during the Dark Ages, after a bunch of bad stuff happens. Lots of wars, the Black Death, the Protestant reformation…

Dreams seem to take on a whole new meaning. While they still seem to be messages from the supernatural they come to be viewed as messages from the devil. Dreams are temptations, demonic visitations and other supernatural evils.

The Nightmare II by Henry Fuseli

A whole culture of fearing evil emerges around this time, ideas of incubuses and succubus’s, vampires and other monsters that feed on dreams and sins and bad stuff that you do while asleep.

This view of dreaming, heavily influenced by the religious climate of the time, would shift as time went by.

How dream integration shifts over the years is a difficult thing to track. Sigmund Freud laments this in his book “The Interpretation of Dreams” saying:

“To write strongly the history of our scientific knowledge of the dream-problem is extremely difficult, because, valuable though this knowledge may be in certain respects, no real progress in a definite direction is as yet discernible. No real foundation of verified results has hitherto been established on which future investigators might continue to build. Every new author approaches the same problems afresh, and from the very beginning. If I were to enumerate such authors in chronological order, giving a survey of the opinions which each has held concerning the problems of the dream, I should be quite unable to draw a clear and complete picture of the present state of our knowledge on the subject.”  – The Interpretation of Dreams

Prior to Freud, dreams appeared to be considered random, a product of an overactive imagination coupled with eating too many spicy foods. Often, dreams were considered in conjunction with sleep, if you were having nightmares, that might be because you were sleeping in the wrong position. It wasn’t clearly understood, and no one was making any progress figuring it out.

In 1899 Freud published Die Traumdeutung. In English it was called The Interpretation of Dreams.

Freud theorized that wish fulfillment was behind most dreams. His interpreted dreams as a reflection of the dreamer’s deepest desires, going back to their childhood. To Freud, dreams were images that held important meanings. Freud’s theory distinguishes two layers of dream content: manifest and latent.

Manifest (superficial) content had no significant meaning but was a mask for underlying issues of the dream.

Latent content was those underlying issues; it expressed unconscious wishes or fantasies.

Basically dreams are our way of acting our dark fantasies and if we didn’t dream, our desires would drive us insane. Further, all the imagery in our dreams can be interpreted as something else. By analysing the context of the dream we can gain insight into our personal psyche.

Carl Jung, a student of Freud, also believed that dreams related to the dreamer’s wishes, which enables them to realize things they unconsciously desire, and that the dreams helps them to fulfill their wishes. Jung believed dreams were messages to the dreamer and that dreamers should pay attention for their own good.  Jung came to believe that dream contents present the dreamer with revelations that uncover and help to resolve emotional issues, problems, religious issues and fears. Jung believed that recurring dreams are a proof that the dreamer is neglecting an issues, thus it shows up repeatedly in dreams to demand attention. He believed that many of the symbols or images from these dreams return with each dream.

While Freud and others tried to understand dreams from a scientific point of view, they still could not explain the methodology of interpreting dreams.  Just like if you go to several different psychics, they’ll all tell you different things, getting your dreams interpreted will often result with several different views on what they mean.

So what’s to be made of all this? Clearly humans haven’t figured out dreaming, that’s what. We clearly suck at that. However that hasn’t stopped us from inventing mythologies to explain it and investigation the human psyche searching for a reason. Today, we still don’t seem much closer to really understanding why we dream. There are theories and some are more likely than others but we still haven’t found that smoking gun that answers the question.

We’ve waited 10,000+ years. We can wait a bit longer.

 

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