Sleep-onset dreams

In order for a sleep onset dream to become a hypnagogic hallucination, the internal stimulus strength has only to achieve a momentary advantage over the diminished force of external stimuli to generate emotionally salient perceptions. Because the prevalent emotion is anxiety, the salient imagery is fearsome, as befits the evolutionary theory advanced above. Better safe than sorry, and Forewarned is fore-armed, as we say. 

So, we may have to settle for sleep-onset dreaming if we want to see the effect of learning on mental content. If we are willing to accept this gift of nature, we may be able to learn from it, as our recent studies of novices learning the video games Tetris and Alpine Racer have taught us. 

Hallucination Enhanced in deep trance Enhanced in sleep onset dreams to markedly enhanced in REM sleep dreams... 

One of the most instructive examples of state boundary crossing is the tendency to experience dreamlike visuomotor sensations at sleep onset. These are called hypnagogic hallucinations if the subject is still awake enough to notice or be aroused by them. Apparently, one need only carry waking brain activation over the sleep boundary and dreaming will im-... 

This normalizing account of hypnagogic hallucinations lends itself nicely to explanation in terms of AIM and hence to integration with those spontaneous and induced alterations in conscious state that interest us most. For example, an exaggeration of the normal tendency to hallucinate at sleep onset is seen in narcolepsy, as well as with the use of clinical and recreational drugs that alter the M axis of the AIM model in ways that promote REM sleep phenomena, including the intense dreaming often associated with it. 

Many narcoleptic patients show a marked intensification of sleep onset REM physiology, making the enhancement of hypnagogic hallucinations easily understandable. Because narcolepsy is also associated with the occurrence of hallucinations on awakening from REM sleep, I will defer discussion of the clinical aspects of the disorder until we have considered these hypnopompic extensions of dreaming into the wake state. 

I consider it to be a matter of fact that consciousness is a continuum of states, that aspects of two or more sometimes distinct states can coexist, that consciousness can be dreamlike even in waking, and that it is likely to be more so at sleep onset. I also know that dreaming can occur in light sleep in the early morning. It thus seems to me quite reasonable to propose that we can explain many of these facts by changes in the level and distribution of activation in the forebrain, and that one forebrain site can become an input source for another. 

Vogel, G., Foulkes D., and Trosman, H. Ego functions and dreaming during sleep onset. Arch. Gen. Psychiat., 1966, 14, 238-248. Reprinted in C. Tart (ed.). Altered States of Consciousness A Book of Readings. New York Wiley, 1969, pp. 75-92. 

Freud s idea that he could avoid suggesting content by laying a client down on a couch (encouraging a pre-sleep relaxation) and sitting behind him or her (to remove any personal impact) seems grossly naive in retrospect. Sleep onset is a particularly fruitful state for the elaboration of fantasy and dream-like mental activity that incorporated local conditions shamelessly. And any patient, hysterical or not, would know - by 1910 at the very latest - what Freud expected in the way of associations . Now that the false memory phenomenon is so well known, it is easy for us to see what mischief Freud s scientific precautions must have cost him. To avoid repeating these mistakes, we need to be much more critical, and much more versatile, than Freud was. 

It turns out, however, that dreaming can also occur at sleep onset (no surprise because the EEG is still relatively activated) and in other phases of so-called NREM sleep, especially late night stage II... 

Following ingestion of mescaline, one first sees spirals, tunnels, funnels, and alleys. Then scenes picturing episodes become connected much as they do in dreams. One sees this very same progression, from geometric forms, through synesthesia, to architectural visions, at sleep onset when... 

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