Brain activation Dreaming

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. 

Isomorphism demands that my emotional brain has activated in parallel with my visual brain in REM. There must be some important differences between the pattern of emotional brain activation in dream one, when I was only slightly anxious and more elated than distressed by the strange visual alterations of my barn, and that of dream two, when I was very anxious about my inability to locate and control the water pipe leaks and furious about my co-workers lack of empathy. 

In dreaming you are not only out of control, you don t even know it You can t keep track of the dream action from one dream to the next or even one scene to the next. I suppose that the three hokey architectures and the three kooky scenarios that I cooked up last night all occurred within one, or at most two hours. For all I know, they could have been my conscious experience of three episodes of selective brain activation/ inactivation of a single REM period. 

Activation-synthesis ascribes dreaming to brain activation in sleep. The principle engine of this activation is the reticular formation of the brain stem, just as it is in waking, but the chemical mode of activation is distinctly different. It is for that reason and that reason alone that dreaming and waking consciousness are so different. In waking, the noradrenergic... 

In a recent Danish PET study of yoga mediatation, Hans Tou and colleagues remark on the similarity of this state s brain activation pattern to that of REM. The absence of anterior cingulate activation in meditation is attributed to the emotionally bland character of the meditation performed compared to the emotional turmoil of dreaming. 

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-... 

Research on the alterations in consciousness caused by sleep has re-centiy been greatly augmented by two sources of evidence that we can scrutinize for instances of complementary enhancement and disruption of function. They are studies of selective brain activation utilizing PET and fMRI neuroimaging techniques, already mentioned in chapters 6 and 7, and the close questioning regarding dreaming of patients who have... 

Imaging of Brain Activation in REM and the Effects of Brain Lesions on Dreaming... 

But the real payoff of exotic dreaming is its naturalism. By virtue of being a product of apparently life-sustaining brain activation in sleep, it is not only necessary but free of charge, free of assault trauma, and free of long-term health risks. 

Sleep is basically divided into two major states - rapid eye movement (REM) sleep and non-REM sleep. These two states of sleep differ as much from each other as either of them differ from wakefulness and therefore early in the modern era of sleep research REM sleep was referred to as a third state of existence [3], REM sleep is a state of dreaming, increased brain activity and variability in breathing and heart function. At the same time, it is a sleep stage where most of the muscles reach their maximum relaxation. The amount of REM sleep does not change much with aging, and remains stable at around 20 % of total sleep. 

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. 

If dreaming is not interrupted by awakening, it is rare to have recall. Poor or no dream recall by many people is a function of the abolition of memory during these brain-activated phases of sleep. As the chemical systems that are responsible for recent memory are completely turned off when the brain is activated during sleep, it is difficult to have recall unless an awakening occurs to restore the availability of these chemicals to the brain. 

The word isomorphism means similarity of form or shape, and brain-mind isomorphism that every form of mental activity has a similar form of brain activity. Therefore, if we detect a dream form, we can seek a corresponding brain form. In dreaming, the simplest example is activation. To explain the awakening of the mind in sleep we should expect to find a similar (but not of course identical) awakening of the brain during sleep. As we see in Chapter 3, we do find this - the brain is electrically activated in sleep and, when this happens, the mind is turned on too. Naturally. It s that simple. 

We are inclined to assume that it is the slow progress of technological development that impeded scientific advances in studying dreaming. But this is a face-saving sop for those who were so conceptually blinded that they could not imagine the simple experiments that could have led to the brain activation conclusion. As Michel Jouvet shows in his novel Chateau du Reve, most of our vaunted twentieth-century discoveries about sleep could have been made earlier by the most useful scientific instrument of all direct observation. The direct observability of sleep is especially easy to achieve in our infants and children, the very individuals who most dramatically reveal the brain activation of rapid eye movement (REM) in their behaviour. 

If you don t have a willing bed partner, you can observe your big sister s baby or anyone s pet cat or dog, and have the same thrill of discovery. Of course you can t expect an answer if you ask them if they are dreaming. But you can answer that question for yourself now that you know that the REMs that give brain-activated sleep its most popular name are a direct readout of the internal activation. Not that dreaming occurs exclusively in REM sleep. It doesn t. REM sleep just happens to provide the most ideal condition for its occurrence. 

It was the combination of EEG and EOG that enabled Eugene Aserinsky and Nathaniel Kleitman to make their 1953 discovery of brain activation in sleep. They called the brain activation phase of sleep REM (for rapid eye movements) because of the association of the activation of the eye movements (oculomotor activation) with activation of the brain. They asserted that dreaming might be another associated event. It was the EMG (together with the EEG and EOG) that allowed Michel Jouvet and Francois Michel to show that muscle tone supporting posture - and hence postural movement - was actively abolished in REM sleep. 

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 1957, William Dement, a co-worker of Aserinsky and Kleitman, vigorously investigated the REM sleep-dream connection in humans, and discovered that cats also had periods of brain activation and REM in their sleep. This provided the experimental model necessary for investigation of the cellular and molecular basis of brain activation in sleep, and the chance to integrate phenomena at the level of cells and molecules with the EEG and the distinctive forms of mental activity in human sleep. We didn t need to know whether cats dreamed to make this integration. All we... 

All mammals have the same kind of brain activation during sleep as humans. Whether or not they dream is another question, which can be answered only by posing another one Do animals have consciousness The answer to that question has been hotly debated. Many scientists today feel that animals probably do have a limited form of consciousness, quite different from ours in that it lacks language and the capacity for propositional or symbolic thought. 

In terms of the important scientific use to which we could put animal sleep in the study of human dreaming, it makes little difference what the answer to the question about animal dreams might be. All we need know, in order to learn from our animal colleagues, is that they have the same kind of brain activation in their sleep as we do. We then go on to make the fairly safe assumption that animals have the same mechanisms of brain activation in sleep as we do. 

Although counterintuitive, the discovery of brain activation in sleep was rapidly accepted by those dream scientists who had sudden and transformative ah-ha experiences when they read about it. In the ensuing excitement about the similarities between waking and dreaming consciousness, few stopped to wonder what bit of this sleep-dependent brain activation could account for the difference, which, after all, is every bit as important as the similarities ... 

---