Neuroscience and Karma: 07. Sleeping

0. Darśanāvāraṇa Karman

In the state of perfection, the soul has infiniteness of knowledge (jnana) and intuition (darśana). The types of karman that obscure knowledge and intuition are respectively called knowledge-covering (jñānānavaraṇa) and intuition-covering (Darśanāvāraṇa). There are nine sub-types of intuition-covering karman which include five types of sleep. The effects of these five intuition-covering karman are felt in

1. sleep with easy awakening (nidrā)
2. sleep with difficult awakening (nidrā-nidrā)
3. sleep while seated or standing (pracalā),
4. sleep while walking (pracalā-pracalā) and
5. sleep accompanied by superhuman deeds (somnambulism) (styāna gṛddhi or styānardhi).

The object of the karman is to deprive the soul of using its faculty of intuiting truth.

It is not difficult to see that the state of sleeping is equivalent to absence of cognition (pratibodha). Conversely, wakeful state is active cognition or intuition.

1. Program for Sleeping

At least once a day, we cease to be conscious - the mind does not operate and only the brain remains partly active as the guardian of our personality and the guarantee of its continuance. When we wake up, we are still the same person as before. At intervals, the program wakes us up for a period of conscious mental activity. There is, therefore, a wonderful opportunity to study the parallel changes in brain and mind as we fall asleep each night and in the morning wake again. By following electrical changes and reports of consciousness, we can see how the activities that we call those of the brain and those of the mind are related, providing together the entity that we call a person, sometimes conscious, sometimes not. Finally, by study of this conscious entity, we shall show how both brain and mind can actually be divided by the surgeon's knife, and also how consciousness is altered by brain-injury.

Knowledge about sleep is therefore important for the study of programs of the brain for several reasons. First, sleep is certainly a state both of the brain and of consciousness. Secondly, no one will question that it occurs following a rhythmic program. Thirdly, it involves a simultaneous change of activity of the whole brain and of the condition of consciousness.

2. Process of Sleeping and Dreaming

Understanding of sleep has been revolutionized by the discovery that electrical activities in the brain indicate that there are two main types of sleep: REM (Rapid Eye Movement) and NREM (non-Rapid Eye Movement) also called active sleep (AS) and quiet sleep (QS).

As a person drifts out of wakeful awareness, his muscles relax; heartbeat and breathing slacken, this is drowiness and if his brain waves were recorded on an EEG, they would show a steady alpha rhythm of relaxation. He may think he is awake, but he is in the embrace of sleep's first stage. The slightest noise could break this fragile slumber.

A few minutes later, the sleeper descends to Stage 2. Brain waves take on the appearance of wire spindles, tracing a dramatic design of peaks and valleys across the EEG paper. The eyes begin rolling slowly from side to side. Although Stage 2 sleep is deeper than Stage 1, it would still take only a slight noise to awaken someone.

Soon a few of the large, slow delta rhythms appear in the brain's wave pattern. This heralds the onset of State 3. The body becomes even more relaxed. Blood-pressure, heart-rate and body-temperature decline. Only a loud noise would awaken the sleeper.

Roughly twenty minutes have elapsed since the onset of sleep. The fourth stage begins. It would be extremely difficult to wake the sleeper from this deepest phase of sleep. Bed-wetting, sleep-talking and sleep-walking occur only in this stage.

Forty minutes have passed. For the next half hour or so, this sleep-cycle will run backwards. From stage 4 back to stage 1. The first dream of the night is about to begin, the sleeper has entered the REM period. In REM, the vital signs change suddenly and dramatically. Breathing, heart-beat and blood-pressure become irregular. Under closed lids, the eyes dance back and forth as though the sleeper were watching a movie. In theory, this is exactly what happens during REM. According to the "Scanning theory", the eyes move around as they follow the action of a dream. During REM, the brain sends a signal to the arms, legs and other large muscles to stop moving. This sleep-paralysis prevents the body from acting out movements occurring in dreams.

The first REM period lasts nearly ten minutes. When it ends, the whole cycle repeats itself, usually four or five times each night. Each cycle lasts an average of ninety minutes. As the night wears on, REM periods lengthen, while NREM periods grow shorter. The final REM period of the night may last as long as one hour, or one-half to two-thirds of the total REM sleep each night.

If a person is woken up during active sleep he will often report that he had been dreaming, whereas this is less common when someone is woken out of quiet sleep. Even a few minutes after a period of active sleep he will not remember that he had dreamt. Here then we have a means of discovering something about the relations between the electrical activity of the brain and the dreaming mind, for surely we regard dreaming as a mental activity. These two types of sleep have been found in nearly all mammals and birds, but not apparently in reptiles or other lower vertebrates or in invertebrates, though many of these show periods of inactivity.

3. Quiet sleep

The program of sleep that is written in the brain thus involves a much more complicated score than would be needed for a mere alternation of sleeping and waking.

Two regions particularly involved in sleep are called the raphe nucleus and locus coeruleus, near to each other in the medulla oblongata at the hind end of the brain. The cells of the raphe nucleus produce the amine serotonin (6-hydroxytryptamine, 5-HT) and deliver it along their axons to nuclei further forward. It is probably released in the thalamus (the gateway to the cortex) and acts upon the cells there to produce the synchronized activities of the cells of the cortex that give the slow waves of quiet sleep.

Studies are beginning to show how two sets of cells interact to produce the rhythm of waking and sleep and the detailed pattern of quiet sleep and active sleep throughout each night. A suggestion is that neurons producing serotonin induce the quiet sleep and then the catecholamines set in action a series of dream-producing neurons.

4. The Programs for Dreaming or Active Sleep

The effect of stimulating the geniculate cells - the dream-producing neurons - is to produce activity in the occipital and other parts of the cortex, which we experience as dreaming during active sleep.

In this, only actual movements are at most a few jerks. So the great cortical activity is accompanied by an inhibition of the motor centers or sleep-paralysis as stated above. It has been found that this inhibition is initiated from a special hinder part of the locus coeruleus. Failure of inhibition of movement occurs in sleep-walking.^[1]

So, the programs for sleeping and for dreaming are quite complicated, and seem to involve periods of activation of the brain but inhibition of the movements that would be expected from their activity. The actions of these various cells of the core brain thus constitute the physical basis or 'script' of the program of sleeping and waking.

5. Functions of Sleep

If there is a program for sleeping, what is its aim and are there feedback mechanisms to ensure that the aim is achieved? Are there some minimum necessary amounts of sleep and of dreaming, and if these are not allowed, is there full compensation by more sleep and dreaming later on? It seems at first obvious that sleep is for rest and recuperation-but why should the brain alone need to recuperate rather than other tissues? The heart for instance never rests.

Perhaps it is a mistake to look at sleep only or mainly as a rest for the brain. It is reasonable to think that many bodily activities require periodical recuperation and that providing for this is the reason for the physiological changes that accompany the various sorts of sleep. The best known are the changes in adrenocorticotropic hormone (ACTH), which controls the secretion of Cortisol by the adrenals, so that it is three times higher on waking in the morning than at midday. Since the adrenal cortex is responsible for promoting many activities that are responses to 'stress', we have here real evidence of the filling of a sort of 'reservoir' during sleep.

Similarly, production of growth hormone (somatotropin) is at a maximum during the first hours of sleep, that is during a period mainly of quiet sleep. After a day of heavy bodily exercise, there is increased quiet sleep.

6. Sleep Requirement

Infants sleep nearly sixteen hours throughout day; children need ten or eleven hours. Most adults average seven or eight hours each night. Middle-aged people require slightly less sleep. In old age, naps become frequent.

The need for sleep increases during pregnancy and illness. Anxiety, depression and physical or mental exertion also lengthen sleep. Researchers theorize that additional REM time - the result of longer sleep - restores the brain and helps it to integrate new experiences. In less stressful periods, demands on the brain are reduced, decreasing REM time. REM deprivation actually benefits some people. In a 1975 experiment at the Georgia Mental Health Institute, patients hospitalized for depression improved when they were deprived of REM sleep. Antidepresent drugs may be effective partly because they supress REM sleep.

Some scientists believe that personality accounts for basic differences in sleep requirements. One study found that long sleepers, those who sleep nine or more hours, are more anxious, introverted and less confident than short sleepers, who get six or less hours of sleep. Long sleepers, the researchers found, often use sleep as an escape from problems. Short sleepers are generally energetic, cheerful and self-confident and are also less inactive than long sleepers.

7. Sleep Deprivation

The program for sleeping is so insistent that it is very difficult to deprive people of sleep. In spite of the demand for sleep, the effects of deprivation are sometimes not so marked as one might expect. After very long deprivation, people suffer from hallucinations and paranoia, thinking they are being persecuted. This perhaps confirms the idea that some sort of reprogramming goes on in the brain while we sleep.

Whatever it is about sleep, that is important, partly relates to active sleep. After deprivation in this way for a night, people show more active-sleep-periods the next night and so on. On the other hand, volunteers deprived of all sleep for three nights have mostly quiet sleep on the fourth, but more than usual active sleep on the fifth. So it seems that both sorts are necessary.

8. Dreaming - Why is it necessary?

The fact that we need active sleep and that it is associated with dreaming has been considered to support the idea that the benefits of sleep come from dreams. Dreams could be regarded as providing for better building of the memory model by continued operation of the mechanism for memorizing during the night, even when no further information from external sources is available.

A dream is a sort of extension and fantasy of life, often expressing urges that are suppressed or disguised during the day. We live out our fears in dreams too, and perhaps we get over them in this way. People who have lived through battles or other terrifying experiences certainly re-live them in dreams for long afterwards, but it is not clear whether this somehow relieves their pain. The theory that dreams are wish-fulfilments is not borne out by hungry or thirsty people, they do not have obviously relevant dreams.

9. Rest and Relaxation

It may be that in looking for complicated explanations for the significance of sleep in ourselves, we are missing its most obvious biological feature which is stillness. We should not exclude the possibility that there is no unique physiological benefit to be derived from sleep, beyond keeping the animal or person inactive/motionless. Many human beings have learned to do with far less sleep than a simple circadian rhythm suggests. There are reports of regular sleepers for whom an hour or even 15 minutes each night is enough.

So it may be that there is no basic physiological need to spend so much of our lives in an unconscious state.

It is found that systematic relaxation achieved by proper technique can replace sleep much more efficiently. Half an hour of total relaxation practised with proved technique can be better than three hours of sleep as far as the rest is concerned.