DREAMING AS PART OF SLEEP: DREAM PHASES-THEIR BIOLOGICAL NECESSITY.
Evidence from prehistoric times to the present confirms that man has always dreamed. In fact, since the time the human brain has slept, man has dreamed. Dreams have always been significant or even uncanny and cause us to do or not to do certain things. One of the oldest and most comprehensive documents on dreams is the Chester Beathey Papyrus 3 dating from 2000 to 1790 B.C., which describes 2,000 dreams and even rates them as favorable or unfavorable in terms of the dreamer's future. Topics recorded show an astonishing similarity to topics of contemporary dreams and include such significant themes as birth, death, possession, loss, aggressiveness, and occasionally even sexuality. The Assyrians also documented dream fixations, and the Greeks, Romans, and Hebrews took over the animistic concepts of neighboring ethnic groups and adopted the methods of dream interpretation used by the Egyptians and Assyrians (Diamont).
In other words, evidence from the prehistoric era reveals a preoccupation with dreams. The scientific era in the field of sleep research is opened up in the twentieth
century/Extensive collections of dreams were made, especially in the United States, and the first significant findings in the field of sleep research included the discovery of the rapid eye movements (REM) that occur during sleep. This led in turn to the earlier mentioned findings about the synchronic and asynchronic phases of sleep. A short time later, a connection was made between the asynchronic sleep phase and dreaming.
Diamont describes his observations of these events as follows: "... evidently something emotional and exciting was going on simultaneously in the sleeping brain." Kleitman then had the brilliant idea, which he initially just called a hypothesis, that the sleepers were dreaming. He decided to test his assumption by attempting, as has already been described, to arouse test subjects.
These historically significant findings were then published in a short article in the journal, "Science," of September 4,1953. Twenty-seven arousals during the REM phase provided detailed descriptions of 20 dreams. As a control check on the reliability of the REM phase as an indicator for dreaming, there were 23 arousals when no rapid eye movements were visible. In 19 instances, the sleepers were unable to recall a single dream (Diamont). On the basis of these experiments, Kleitman made the first description of the sleep-dream curve.
Further findings, especially those made by Dement, who was already a scientific colleague of Kleitman while still a medical student, resulted in long-term research, and finally there were 2,500 monitored hours in the first test series available for evaluation. As a result, it was possible to determine the relation between the time spent sleeping and the time spent dreaming). It was shown that the total time spent in sleep by numerous middle-aged test subjects amounted to an average of 7 hours and 2 minutes and that the total time spent dreaming amounted to 82 minutes, or about 20% of the night.
For the first time, it became abundantly clear that night after night a series of dreams takes place, regardless of whether or not we are able to recall them.
What happens when dreaming is effectively impeded was already covered in the description of the REM phase of sleep and in the explanation of their significance. Since Dement's experiments contain such vivid descriptions, they are again included here in some detail. Some volunteer test subjects were permitted first to spend several nights in the sleep laboratory in order to become accustomed to being there. Their sleep behavior was then observed and recorded. Special attention was given to the synchronic and asynchronic sleep phases. The occurrence of dreaming was then impeded for five nights. Test subject A, to be quoted later, was impeded from dreaming for seven nights. Therefore, when A later fell asleep, the EEG showed that a new sleep cycle began immediately, which went through all phases of sleep to the wave trough and, again coursing through all phases of sleep, ascended to the wave peak. The next dream phase started at the expected time, about 90 minutes later, and A was again awakened. The following night, A tried to dream with increasing frequency. For this reason, he had to be awakened with increasing frequency to impede him from dreaming. During the second night, A attempted to dream 10 times, in the third night 17 times, in the fourth night 21 times. Finally in the seventh night it was necessary to awaken him 24 times to keep him from dreaming, because A tried to launch two dozen different dreams. In the following night of recuperation, during which brain wave tracings were also made but without awakening the test subject, 2 hours and 40 minutes of an 8-hour period of sleep were spent in dreaming, i.e., one-third of the night, or almost twice the usual amount. The same was repeated during the second night of recuperation. The unavoidable conclusion was that A experienced REM rebound, which means that he made up for dream deprivation by doubling the amount of time spent in dreaming. As a rule in these experiments, after four or five nights of dream deprivation, dreaming increased for about five nights.
These decisive experiments clearly revealed the necessity of dreaming. Every person requires a relatively constant amount of time for dreaming in order for sleep to be restorative. Serious disturbances can otherwise result.
Manifestations occurring during consistent dream deprivation parallel to an astonishing extent the findings of Canadian research in sensory deprivation. These findings show that if sensory impressions are withheld from a person for a certain "period of time, the result is confusion in sensory perceptions and ultimately hallucinations.
Although very thorough and extraordinarily comprehensive research has in the meantime been conducted on the relation between REM phases and dream stages,
some reasons must be given for not making a too schematic equation between the REM stage and dreaming (Rieger). For one thing, there is no real proof that dreaming does not also take place during the synchronic, deep sleep phase. It is possible that some mental activity is present during this period but that it simply cannot be recalled, just as a large number of "non-dreamers" are unable to recall a single dream immediately after the conclusion of an REM phase. According to all our knowledge of the function of the brain, it must also be assumed that the activity of the cerebral cortex is necessary for the creation of dreams having concrete optic-motor content-i.e., dreams having pictures and action. But we also find REM phases, even particularly abundant REM phases, among newborn infants and animals whose cerebral cortex is not sufficiently developed to differentiate, assimilate, and reproduce optical impressions in a dream. Since a newborn baby, unlike an adult, is not able even in a waking state to stare at objects, the interpretation that would otherwise probably be accurate-that the rapid eye movements result from dream pictures-cannot be supported. Even a person blind from birth who cannot have visual dreams manifests typical REM phases. Even a cat whose cerebral cortex has been removed through an operation and which can surely no longer dream still shows the REM phases with their characteristic lively eye movements, cessation of muscle tension, muscle quivering, and changes in the heart, circulation, and respiration. What we define and measure as the REM periods of sleep are therefore already present (preformed) early in the individual development of the human and in the phylogeny of mammals. The dream, however, only begins to fill this physiological development with content when differentiated functions of consciousness become possible. More simply expressed, dreaming does not bring about the REM phase, but the REM phase seems to some extent to be a condition for dreaming (Rieger).
There is in all of this some comforting knowledge for problem sleepers. Even short dream periods usually occur during what seems to be a long, sleepless night. The body simply cannot do without these dream periods and is evidently able to get them, even against considerable obstacles, for they constitute a regenerative process and provide a feeling of recuperation. If one has learned, perhaps by means of autogenic training, to be quiet, doesn't get nervous, and relies on the short, dependably occurring dream phases, a sleepless night can be passed without, relatively speaking, any ill effect. Even a sleepless night offers rest and REM periods, which are the most important elements of sleep. It is possible mentally to come to terms with a sleepless night, and the subjective feeling of being rested is measurably increased.