Another fairly short post a week 2011 entry, and on time for once! As I've mentioned in an older post I have a few sleep disorders, and this can mean going for periods with very little sleep. It rarely means no sleep at all, just that it's in short supply and of poor quality. There have been occasions though where I've not slept for days, and though I can't remember exactly how long the worst occurence may have gone on for I do remember some of the strange experiences that sleep deprivation has caused.
The most common experiences after a couple of days without sleep (in my experience) are hallucinations. Now I'm not talking anything as grand as an imaginary conversation with an unreal person, however your tired brain tends to start making mistakes and you interpret things differently. The first stage is always auditory. I used to hum/sing myself to sleep when I was a young child and even now when I'm on the verge of sleep I tend to have some melody running through my mind. It may be entirely coincidental, but after a couple of days without sleep I start to hear snippets of familiar music, barely audible and unrecognisable. I've always assumed this is by brain recognising the wrong patterns in every-day background noise.
The second type of hallucination is one regularly reported by people with certain sleep problems, and it's shadowy figures on the edge of vision. They're always moving, very quickly, flitting in my peripheral vision. indistinct and yet somehow decidedly humanoid. The thing here is that peripheral vision is largely created mentally anyway, the eyes read very little of the information for this region of your sight and the brain quite literally imagines what detail you do perceive based on your expectations and knowledge of your environment. It's easy therefore for this to be misinterpreted. We've all glanced over at something we thought we saw out of the corner of our eye only to find it was something else entirely.
Still, it's quite a spooky experience.