Consciousness - An Introduction (ch23)

What do sleep and dreams have to do with consciousness? - Chapter 23

You can speak of a lucid dream if, during the dream, you realize that you are dreaming. So you are aware of the fact that you are dreaming during your dream .

 Waking and sleeping

Every day we take cycles with three states: (1) being vigilant, (2) REM ( Rapid Eye Movement ) sleep and (3) non-REM sleep . A cycle repeats itself four to five times a day. These sleep phases are classified based on physical measurements and behavior measurements.

For example, during REM sleep, the brain is very active and the EEG pattern resembles that of someone who is awake. Yet it is more difficult to wake someone up in REM sleep than during non-REM sleep. During the non-REM sleep there are mainly long, but slow waves to be seen on the EEG. Adenosine is the most important neuromodulator that induces sleep.

The REM cycle is guided by the reticular formation in the pons of the brainstem. Here are nuclei that constantly brake and activate REM sleep. Sensory input is blocked by the thalamus and the cortex during the non-REM sleep. During REM sleep, the brain blocks motor skills. Someone seems to be paralyzed during sleep. 

When people wake from a non-REM sleep, people often say that nothing has gone through their heads or that they have not thought of anything during their sleep. Reports of non-REM dreams are often short and have few details. When people wake up during the REM sleep, they often say that they have had a bizarre and complex dream.

Research shows that there are similarities between the dreams that people have. Even the dreams in different cultures appear to be comparable. Men dream more often about men than women do. They also dream more often about aggressive interactions with other men. Children often dream about animals and are often the victim of aggression in dreams.

There are several problems to generalize the above to all dreams, because of the effects of the method of collecting dream reports. Many different results are found in studies, for example on the prevalence of bizarre dreams.

Hobson drew up three categories to show that bizarre dreams can take different forms. These categories are:

1. 'incongruity': the non-matching of characteristics of characters, objects, actions or settings;             

2. 'discontinuity': sudden changes in the above elements;             

3. 'uncertainty': explicit vagueness.

Research suggests that the way characters and objects are transformed into dreams follows certain rules, but that the changes of a scene and a plot do not.

The AIM model

Hobson designed the AIM model about sleep. AIM stands for three different dimensions of sleep:

1. activation energy (measured by EEC patterns),        

2. input source ( external or internal ) and        

3. mode (the ratio amines and cholins ).

During the awake state, amine neurotransmitters and neuromodulators (such as norepinephrine and serotonin) are dominant and necessary for rational thought, voluntary action and attentional focus. During REM sleep, acetylcholine takes over and thoughts begin to assume a delusional and irrational form. The ratio that Hobson speaks is therefore about the difference between the waking state and REM sleep.

According to Hobson, sleep phases can be distinguished on the basis of values ​​on these three dimensions. He has designed a cube model for this. He added a fourth dimension to this, namely time. As a result, the values ​​of A, I and M change.

Edelman and Tononi state that a unified consciousness depends on the constantly changing dynamic core of activity in the brain. This dynamic nucleus would be supported by connections between the cortex and the thalamus. This would lead to integration, but there would also be changes that continue in the brain. During the non-REM sleep, consciousness would disappear.

Dreams and REM sleep

Many physiological, neurochemical and behavioral variables are related to subjective descriptions of a dream. However, the measured correlations are not perfect. However, it seems certain that people have vivid dreams during REM sleep, while these dreams rarely occur during non-REM sleep. Being in the REM phase does not necessarily mean that you are dreaming at that moment. You can also dream without being in the REM phase.

The REM phase is therefore not necessary (but not always sufficient) to dream. In addition, REM sleep can occur if people do not (can) dream. For example, fetuses are in the REM phase for fifteen hours a day, but they can not dream about anything because they have no experiences yet. When they are born, the time spent in REM sleep becomes shorter and shorter. Blind people do not dream in terms of images, but in terms of words and ideas. As children grow older, their dreams are increasingly related to their cognitive skills. When they are about five years old, their dreams begin to become more lively. In addition, there is more and more movement in their dreams. Reptiles do not have REM sleep, but birds and mammals do. We can not know if birds and mammals have dreams,even though they are in the REM phase during their sleep. The question is whether subjective experiences and physiological processes in the brain are the same.

Dreams and experiences

Are dreams conscious experiences? Many scientists think so. If you dream about yourself, your 'self' in the dream often does not realize that he or she is in a dream. This ' dream-self' also carries out actions that you would never have carried out in daily life. Your 'dream-self' therefore behaves differently from yourself. In the previous chapter, an ASC is defined as a changed state of consciousness that someone is aware of. In your dream, however, you often do not realize that you are dreaming. In that case, there would therefore be no ASC. A lucid dream , on the other hand, would be an ASC, because in such a dream you know that you are dreaming.

Dreaming takes time, it is not that you start a dream just before you wake up. Dennett speaks about the ' cassette theory of dreams' . This theory states that the brain stores potential dreams. If someone wakes up from REM sleep, a ' cassette' would be taken from the storage place in the brain, making it seem like we had dreamed. This theory states that dreams actually do not exist at all. We do not dream, but we feel that we have dreamed.

So there are two ideas about dreams:

1. there are dreams that occur in consciousness or are presented to consciousness during sleep, and             

2. dreams arise unconsciously during sleep and are 'remembered' when someone wakes up.             

We will probably never know which of the two is correct. In addition, there is also the ' retro-selective theory' (also called ' backwards-weaving theory' ). This theory states that during the REM sleep all sorts of brain processes are in progress. These processes are not 'inside' or 'outside' consciousness. When someone wakes up, he makes a story by selecting one of the many possible stories that are in the memory. These stories have been produced by all kinds of brain processes. This theory states that dreams are not conscious experiences, since they do not occur in consciousness. According to this theory, there is nothing that occurs in consciousness at all.

Rare dreams

Sometimes it happens in a dream that there is ' false awakening' . In that case, the dreamer dreams that he or she has woken up. It also happens that people at 'false awakenings' see a green glow or hear buzzing noises. These experiences are similar to hallucinations. Experiences where the entire environment has been replaced by hallucinations are sometimes called 'metachorical experiences'.

Lucid dreams

In a lucid dream is it that while dreaming you know you are dreaming. Sometimes people say that in lucid dreaming they can influence what they dream. You could say that the consciousness is the cause of this, but we can not draw this conclusion.

For a long time, lucid dreams were only examined by parapsychologists. Many psychologists did not believe that there is such a thing as a lucid dream. Self-reflection and making conscious choices would be impossible while dreaming, so lucid dreams should arise before or after sleep. Hearn and LaBerge proved that this view is not correct. During REM sleep, the muscles are paralyzed, so that someone can not say that he is experiencing a lucid dream. Hearne and LaBerge discovered that someone can make eye movements during REM sleep.

Research has also shown that lucid dreams last about two minutes, although they can also last fifty minutes. Lucid dreams often arise when there is a lot of alertness during REM sleep, but also when there are pauses in the breathing and small changes in the heart rate. In addition, there is an increased activity in the left parietal lobe. This may have to do with the more solid self-awareness in a lucid dream.

Research shows that eye movements go hand in hand with the contents of a dream. For example, someone can dream about a tennis match and this can be seen from the eye movements he makes from left to right. The nervous system is also involved in the physical actions that are being dreamed about.

Brain scans show that when we see or hear something, the same sensory areas are activated as when we only imagine it. The same seems to apply to dreams. Thus something about the dream content can be said on the basis of activation patterns. You can discover whether someone dreams about emotions or about memories. Voluntary breathing during lucid dreaming corresponds to how normally breathing is. There are techniques to cause lucid dreams. These techniques often go hand in hand with special equipment, such as the 'dream machine' from Hearne and LaBerge's MILD technique. This latter method is based on the idea that we spend a lot of our time in an alert state and that if we are more lucid this vigilance turns into dreams.These methods are equal to those of meditation and mindfulness.

Resources: Blackmore; Susan. (2010). Consciousness, Second Edition An Introduction. Abingdon, Oxon: Taylor & Francis.