Wednesday Science Limerick: Nightmares

The Nightmare, by Henry Fuseli (1781)

When you wake, with a shock, in dispair,
With a monster that looks like a bear
It is not what it seems
Its a beast in your dreams
So don't panic its just a nightmare

Earlier this year I attended a very interesting talk "The Psychology of Ghosts and Hauntings" by Professor Chris French, at a meeting of the Chiltern Humanists. Prior to the talk I was aware of most of the different types of human mental failings he mentioned and I was delighted with his well chosen examples and references to the kinds of research projects that have been carried out.

One thing which particularly excited me was the discussion of sleep paralysis, which provides an explanation of why, when you dream you are running down the street, your legs don't move. I had not come across this condition before and it is relevant to the model of the brain's internal language I am developing, by demonstrating that there is a well known blocking mechanism.

This lead to my reading up topics such as sleep, rapid eye movement, parasomnia, nightmares and sleepwalking on Wikipedia and I get the impression that, like other areas of brain studies there are a lot of ideas as to what is involved - nut a lot more needs to be done. What is clear is that many species of animals sleep and that the brain is clearly very active for at least part of the time were are sleeping. As such there must be a good evolutionary advantage in sleeping which involves the brain, which appears to be refreshing and rehearsing the information it has accumulated when it was awake. However it would not help if the sleeper physically re-enacted the actions of the day and the brain has a mechanism to switch off brain activity which would lead to concious awareness of the dream, and the associated bodily movements.  Sleep problems, such as night terrors and sleepwalking, can be related to these switches failing to work correctly and on one hand you imaging your brains rehearsal as real but cannot move, or that your body moves but you are not aware of what is happening.

www.vector.rs

His thoughts were so far from the floor
That he dreamed that in clouds he did soar
Till he tripped on a boulder
And so tumbled over 
And won't walk in his sleep anymore.