Sleep labs

University of California, Davis, UC Davis Sleep Lab, 1712 Picasso Ave, Suite B, Davis, CA 95616, USA... 

To have such vivid consciousness while asleep is paradoxical. Because the memory for dreams is so fleeting, it would be natural to assume that the dreams occurred in the instant before awakening as a by-product of the brain activation process causing me to wake up. But this hypothesis is incorrect, or at least incomplete. We know this because had I been sleeping in a sleep lab, instead of my bed at the Hotel Miramare in Strom-boli, a distinctive constellation of physiological events would have preceded my awakening—perhaps by as long as 30, 40, or even 50 minutes. 

Even though my retinae are unstimulated by light, we know from our sleep lab EEG recordings that my visual sensory brain is activated, and we know from our EOG recordings that my visual motor brain is activated, too. If we put two and two together, we can speculate that my dream vision is the sum, or perhaps the product, of these visual activation processes. 

As Mark Solms points out in his recent book, the dreams of patients with temporal lobe epilepsy are more intense than those of normals. They are more frequently intensely unpleasant or nightmarish, and this is presumably a function of higher levels of anxiety mediated by the hyperexcit-able amygdala of the epileptic patients. These hypotheses are testable in two ways. One is to confirm the anecdotal reports of patients by studying the subjects in sleep labs, as Jose Calvo and his group have done in Mexico City. Compared to age- and sex-matched controls, the epileptic subjects had measurably higher levels of anxiety in their dream reports. 

Sleep lab recordings reveal that in the first three days following alcohol withdrawal, the REM sleep rebound becomes so intense as to practically displace the NREM sleep that alcohol had initially enhanced at the expense of REM. This is REM debt payback with a vengeance. As the subject becomes more and more tremulous, more and more delirious, and more and more seizure prone, REM sleep levels go to 100 percent of sleep, indicating a marked shift in brain excitability that we assume is related to a desperate attempt of the system to restore neuromodulatory equilibrium. 

Did you ever see a dream walking asks the popular 1940s love song, Well, I did. And so did Carlos Schenck and Mark Mahowald when they recorded patients with the REM sleep behavior disorder (RBD) in their sleep lab. In chapter 8, I described the dramatic emergence in the REM sleep of some middle-aged people of motor acts that bore a 1 1 relationship to the subjective experience of dream movement. 

All human beings who have been studied in sleep labs have brain activation in sleep. Periods of brain activation during sleep are associated with rapid eye movements in the sleeper. These rapid eye movements give the brain-activated phase of sleep its name REM or rapid eye movement sleep. When awakened at the time of intense clusters of rapid eye movements, 95 per cent of sleepers studied in labs report dreaming. From this evidence, it is generally assumed that everyone does, in fact, dream in sleep any impression to the contrary is related to the difficulty recalling dreams. 

These reports do, however, have corresponding deficiencies, which need to be overcome if dream science is to be universally valid. To test the generality of the findings and to be sure that I wasn t just making up dreams to fit my theory, we need to have reports from many other sources and individuals, collected under very different conditions. The dream data that we have analysed before arriving at our conclusions have thus been taken from other dream journals, sleep lab reports, and home-based reports. 

We know that sleep lab awakenings change the character of the reports in at least two ways. 

A major disadvantage of sleep lab reports is that they are very expensive to obtain and tend to come almost exclusively from younger individuals. Students at the universities where the labs are located are easily recruited. Finally, due to expense, they tend to be limited in number of reports per participant. No one who is a sleep lab participant can yet match the 256 reports of the Engine Man, or my 300+ reports. 

But, in reality, it s even easier than that. For anyone to observe REM sleep behaviour directly, it can be done with bed partners, especially in the wee hours of the morning, most conveniently on vacation, in the summer time when the hillock of the cornea can be seen in the early dawn light to glide to and fro under the closed - or perhaps half-open - eyelids. The eyelids themselves dance and twitch sporadically and, when they do, one has only to give a light tap on the shoulder and ask what is going on in the mind. Informed consent is as admirable in these informal conditions as it is in university sleep labs, but don t let that stop you. 

The point of this introduction to sleep lab science is to show that, although technology was not really necessary to describe dreaming scientifically or to describe sleep behaviourally (because both could have been done via careful direct observation), it was indispensable in showing that brain activity is continuous - and continuously variable - in sleep. 

In every case, the dream report given by the patient on being awakened fits with the motor behaviour observed during the REM sleep dream. We know that these events occur in REM sleep from sleep lab evidence. 

Kales et al. (1991), in a placebo-controlled sleep lab study, showed that even under brief, intermittent administration and withdrawal of triazolam (and, to a lesser extent, temazepam), patients experienced rebound insomnia, thereby predisposing to drug-taking behavior and increasing the potential for drug dependence. ... 

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