The Neurophysiology of the Brain: Its Relationship to Altered States of Consciousness (With emphasis on the Mystical Experience)

by Dr. Peter Fenwick, Consultant Neurophysiologist to St Thomas's Hospital: Bethlehem Royal Hospital and the Maudsley Hospital: Institute of Psychiatry


Mystical experience has been part of man's nature for thousands of years. Each culture has used these experiences as a basis for their religious practices. Many cultures have devised techniques to produce the mystical experience on demand, while others have found methods which, if practiced by the devotee over many years, allow a different state of subjective consciousness to arise.

However, before discussing religious experience, it is necessary to ask questions about experience itself and personal consciousness and whether or not there are any clear answers as to how we should approach this.

Consciousness arises because of a series of complex actions taking part in the normally functioning brain. By consciousness, I mean the appearance within me of an experiencing self that is able not only to know itself but also is able to differentiate a group of experiences which clearly are not part of itself or part of the body to which it belongs, in fact they come from the outside world. Wigner (1964), in his article `Two Kinds of Reality' summed this up when he said 'There are two kinds of reality of existence; the existence of my consciousness and the reality of everything else. The latter reality is not absolute, but only relative''..excepting immediate sensations and, more generally , the content of my consciousness, everything is a construct, but some constructs are closer, some farther from the direct sensations..'

Schrodinger (1958) in his excellent book `Mind and Matter' takes the problem a stage further when he says 'The World is a construct of our perceptions, sensations and memories. It is convenient to regard it as existing objectively on its own. But it certainly does not become manifest by its mere existence. Its becoming manifest is conditional on very special goings-on in very special parts of this very world, namely on certain events that happen in a brain. That is an inordinately peculiar kind of implication which prompts the questions: 'What particular properties distinguish these brain processes and enable them to produce the manifestations'

Thus we have primary reality which is the domain of the experiencing self and we have secondary reality which is the interpretation of the outside world by the complex functioning of the nervous system. This is the external reality and it is secondary to the primary reality of the self.

As Schrodinger says, 'It is convenient to regard the world as existing objectively on its own but in fact it is simply a construct of our sensations, perceptions and memories'. The world we see or experience depends on our state of brain functioning, alter this and you change the world. This immediately raises the questions of objectivity of the external world and possibly more important, of the objectivity of the way we strive to understand the world, in fact of the objectivity of science. If the external world depends on the structure and functioning of the brain, where then is objectivity'

Martin Deutsch (1959) in an article entitled `Evidence and Influence in Nuclear Research' states: 'The more carefully we peer at the faces of our meters, therefore, the more we see the reflections of our own faces'.Even in the most up-to-date physical concepts the anthropomorphic burden is very large. Particles still attract or repel one another rather as do people, they experience forces and are captured or escape. They live and decay. Circuits `reject' some signals and `accept' others, and so forth'.

In other words, we construct a `science' from our own internal experience and it thus has the characteristics of ourselves and the culture of the day. After all, our culture is the vehicle by which we understand the events of the world around us. It is necessary to raise and to emphasize the question of the objectivity of the outside world and indeed of our own experience. Let me stress again, that subjective and objective consciousness depend for their expression on the normally functioning brain. Mystical experience has both subjective and objective correlates, i.e. the personal subjective consciousness of the individual appears to be affected as does his view of the external world. There is nothing to suggest that mystical experience is in any way qualitatively different from other subjective or daytime experiences although it may of course differ in degree. So with the understanding that mystical experience is dependent on a particular dimension of brain functioning, let us first look at the classifications of mystical experience and then at brain function to see if there are any insights available to us as to what is the neurophysiological basis of religious experience.

And so now to an examination of the higher states of consciousness and their distribution in the population. There is not time to review the field in detail but religious experiences of a wide kind are very common. Greely and McCreedy found over 35% of people in a national sample, equivalent to a population polled of 45,000,000, to have had a near ecstatic experience. Their respondents said they `had the feeling that you are very close to a powerful spiritual force that seems to lift you out of yourself'. Wuthnow in 1976 reported a 50% positive response from a random sample of 1,000 people in San Francisco, California, to a question about religious-type `peak experience'. In Nottingham University amongst post graduate students, David Hay has reported a 65% positive response. So we are not dealing with an isolated phenomenon but with an experience which is very much part of the psychic life of a large proportion of the population. Interestingly, Greely and McCreedy, in their study, measured using the Bradburn scale the psychological well-being of their respondents. They obtained the highest mean score of any group every measured on this scale for psychological well-being, showing that people with this experience are well-adjusted members of society. It was fairly evenly spread amongst the whole age range.

In Hay's study, if the experience was said to have affected the person's life, it was in a positive direction, making him either happier, his life more meaningful, himself more aware and adding personal depth. As religious experiences are distributed so widely in the population, do these differ in any way from the broad universal experiences of the mystics' The difference is probably only a question of degree, for the same features are claimed for both. An example is given by Bucke, a Canadian Psychiatrist, who at the turn of this century in his book 'Cosmic Consciousness', gives nine criteria which describe the mystical experience and the age of onset of cosmic consciousness. An experience by C.M.: 'Now came a period of rapture so intense that the universe stood still as if amazed at the unutterable majesty of the spectacle! Only one in all the infinite universe. The All-caring, the Perfect One, the Perfect Wisdom, truth, love and purity! And with the rapture came insight. In that same wonderful moment of what might be called supernal bliss, came illumination. I saw with intense inward vision the atoms or molecules of which seemingly the universe is composed – I know not whether material or spiritual – rearranging themselves as the cosmos passed from order to order. What joy when I saw there was no break in the chain – not a link left out – everything in its place and time. Worlds, systems all blended in one harmonious whole Universal synonymous with Universal Love'.'. Mazlow has formulated a rather broader scheme listing twenty five points which he feels describe what he calls `peak experiences'. Both authors refer to the same experiences; the main ones given by Mazlow are:

(1)The whole universe is perceived as an integrated and unified whole.

(2)The cognition or experience when it comes is fully attended to.

(3)The world is seen as part of nature rather than as part of human destiny

(4)The perception is egoless, transcending.

(5)The experience is self validating and seen as highly valuable.

(6)The experiences are ends in themselves.

(7)There is frequently a lack of consciousness of time and space.
Phrased positively, this is like experiencing Universality and eternity.

(8)The world is seen only as beautiful, good, desirable and worthwhile.


In examining all the replies to his questionnaires about peak experiences, Mazlow defines a set of experiences called `B' values, fourteen in all which relate to the intrinsic values of the individual's Being. (Mazlow 1964)

Deikman has written widely about the mystical experience but he sums it all up when he says it has five main features:

(1)Intense realness, more real even than ordinary experience.

(2) Unusual sensations, e.g. being wrapped in light or a flame coloured
cloud, or hearing enchantingly lovely music.

(3) The feeling of unity, that the individual and the whole cosmos is one.

(4)Ineffability, being unable to speak about it because the experience is outside the range of normal experience.

(5)Transensate phenomena or experiences which go beyond and are different from the usual sensory experiences of ordinary life.


The Marharishi Mahesh yogi according to his tradition also defines a hierarchy of consciousness which, because of the success of the Transcendental Meditation movement, is now known very widely indeed. This progression starts with ordinary consciousness from which, if manipulated by meditation, springs transcendental consciousness whose property it is to transmute ordinary consciousness to cosmic consciousness then to God consciousness.

Whatever system of mental discipline one uses to illuminate and advance one's growth spiritually certain features of the higher states of experience are common to all. These fall into two types, those which remain once the experience has receded and those which are only present during the time of the experience, the tonic and the phasic.

The phasic features relate to the actual content of the experience, for example, the perception of a flame coloured cloud, or seeing with the inward eye the very atoms of which the universe is composed. Changes of emotion are also phasic in that they rise to a peak of intensity at the height of the experience when feelings of universal bliss and love occur. These then wane with the experience. Cognition is also altered temporarily with the feeling of `I' changing from the limited to the universal. With the experience there also comes the feeling of certainty, that what is perceived is true, no other form of validation is required.

Following the return to ordinary consciousness many people are entirely changed by their experience of the universal. As Bucke says, they lose their fear of death, they have a changed attitude to both themselves and their lives, and many people following such an experience change their mode of living and their beliefs. Of considerable interest are the changes in cognition and certainty which occur.

Some rare people, after such an experience, enter a new sensory world seeing a pulsating golden haze underneath every sensory impression. An example of this, quoted by Guru Raj Ananda Yoga, follows:

'What I experienced after that meditation was that everything seemed covered with a golden haze'I can perceive, I can look through a person completely beyond the body and beyond the mind and perceive this beautiful pulsation which seems to radiate as joy. Now that joy does not remain separate from the joy which is within you which identifies itself entirely, so one does not experience any separation from anything existent and that joy could be seen, observed and experienced in the meanest little insect which crawls on the ground, to the highest evolved plan.'

So it is clear then in summary that there is a change in cognition, a new sense of `I'; in emotion, wide feelings of universal bliss; and in sense perception – the universal golden haze. How then can we account for these from the point of view of brain function' All these three areas have brain systems devoted to them so I suggest we now look in some detail at how the brain functions. Much of the introduction to the next section will be well known to many of you but I would ask those of you who are familiar with it to have patience while we go through it for the others.

The human brain is the largest, when compared to the weight of the body, in the animal world; its volume is about 2,000 ccs; the woman's brain is slightly smaller than man's by about 50 ccs. The most prominent part of the human brain is the cerebral cortex; the mantle of cells situated on the outside of the brain surrounding and covering the structures situated more deeply the thalamus, hypothalamus and brain stem. The cortex can be divided up into four major lobes, each of which is known to have a group of specific functions which it sub-serves. The frontal lobes are related to planning, judgment and the control of motor activity in movement; additional functions are bladder control, coordination of pursuit movements of the eyes and in a complex way not yet fully understood the control of motivation and anxiety. The parietal lobes situated further back than the frontal lobes are involved in the perception of bodily sensation, the feeling of three dimensional objects in space, calculation, and the synthesis and maintenance of the body image. At the back of the brain are the occipital lobes which are concerned with the synthesis and perception of our visual world and its coordination with the other senses. Underneath the parietal lobe and springing forward from the occipital lobe is the temporal lobe, an area of brain that is at the centre of current scientific interest. This lobe deals with the perception of sound and in its deeper parts the perception of smell. However, there are deep within its substance the structures whose function is very different from simple analysis of the brain, the precise functions of which are not yet entirely clear. These structures are called the hippocampus and the amygdala and they are connected by important fibre tracts to deep structures in the centre of the brain, the hypothalamus. This system is called the limbic system. The hypothalamus is connected with the body appetites such as hunger, thirst, temperature, the sexual drive, fright and flight, relaxation, etc. The hippocampus is known to be associated with the filing away and recall of memories, while the amygdala is thought to be concerned with motivation: certainly there is evidence that aggression, fright and other emotional states are intimately related to amygdalic activity. This has led to the idea that the limbic system is concerned with adding the emotional tone to the world which is created for us by our brain. Considerable scientific doubt has now been thrown on this concept and it would be wise to consider the whole area as still unknown. A recent symposium in 1978 (Ciba Symposium No. 56) suggests that the limbic system may be more involved with cognition rather than emotion. However, having said this, there is no thesis of emotion and that abnormalities of functioning in these structures produce mental states in which emotional changes occur, fear and anxiety are common but ecstatic states also occur, although less frequently.

The temporal lobe is also concerned with the feelings related to the sense of `I'; it appears to generate the feeling of `I' and then adds to it the feeling of familiarity or strangeness that is evoked by the perceptions that are fed in through the senses of hearing, vision, etc. Thus when looking at a landscape the feeling of familiarity or strangeness is provided by the temporal lobe while the actual perception of the landscape takes place in the occipital lobe, the feeling of the viewer of the landscape is the temporal lobe. Disorders of the temporal lobe can thus cause sensations of familiarity or strangeness, déjà vu or jamais vu, feelings of certainty and wide emotional feeling states both negative and positive. One can thus see that many elements of the mystical experience are to be found in this area, indeed as we shall see later there is considerable evidence to suggest that the temporal lobe is concerned with the mystical experience and that disorders of function in this area can lead to the genesis of spontaneous mystical experience and can also produce personality changes which have as one feature excessive religiosity.

We must now pass on to examine other brain areas which are also important, although we will be returning to the temporal lobe and the limbic system later on.

Linking the deeper structures of the brain, the thalamus and hypothalamus, to the spinal cord is the mid-brain and then the brain stem. Amongst other functions the mid-brain is concerned with mood while the brain stem contains the life support systems; these structures which control respiration, heart rate, blood pressure and control consciousness and the sleep wake cycle. Thus both mid-brain and brain stem structures are likely to be important in the mystical experience.

That then is a quick over view of the structure of the brain with special emphasis on those areas which are likely to be involved with the mystical experience. I would like now to change the level at which we are looking at the brain and to examine the elements of which it is composed. The basic element of the brain is the neurone or nerve cell. This consists of the cell body and elongated cell processes, the dendrites, through which the cell receives its input from other cells surrounding it and from other cells situated at some distance. When the cell fires the output is conducted down the axon, a long fibre which runs from the nucleus of the cell over a great distance to end in small terminal processes which join on to the dentritic tree of other nerve cells. The joining of one cell to another is called a synapse. There is no direct electrical connection between the axon of one cell and the dendritic processes of the next, in fact there is a gap called the synaptic cleft. When the nerve cell fires an action potential sweeps down the nerve axon to arrive at the synapse. At the synapse it causes the release into the synaptic cleft of a small packet of chemicals which cross the cleft to affect the cell membrane of the next nerve. These chemicals are called neurotransmitters. There are several different neurotransmitters, some of which are excitatory, that is they stimulate the next cell, and others which are inhibitory, that is they prevent the next cell from discharging.

The neurotransmitters of one kind tend to occur in systems, this means that a whole group of neurons all connected with the same function may use the same neurotransmitters, an example is the transmitter dopamine which is found in the losalganglia, a group of cells deep in the centre of the brain in the thalamus whose function is connected with the coordination of movement. A lack of dopamine can lead to tremors and muscular rigidity as seen in Parkinson's disease. Other neurotransmitters are involved in other systems, for example the system which is involved in the onset of sleep uses the transmitter serotonin; that involved in awaking and in the Rapid Eye Movement phase of sleep is nor-adrenaline.

The important point to understand is that when a nerve cell fires, neurotransmitters are released to propagate the impulse from cell to cell. The neurotransmitters are arranged in systems and that each system can have a specific function or group of functions. Alteration in the neurotransmitter balance can lead to alterations of functioning within the system. Of great importance is the discovery over the last decade that there are neurotransmitter systems which underlie mood and others which are involved in the processes of perception and thinking. Those responsible for mood are the neurotransmitter amines of which nor-adrenaline is one of the most important. Too much, and mood swings high to give the picture of hypomania, too little and mood swings down into depression. Those brain systems involved in the alteration of mood are likely to be involved in the mystical experience. Not infrequently during a hypomanic episode, due to an upswing in mood, patients report fragments of the mystical experience. Feelings of unity and universal love are common, a change in the quality of experience is described, with the world taking on a different and shining appearance. Some individual in the ward may be transfigured with light seen shining from them and illuminating the room.

The neurotransmitter thought possibly in part to be responsible for perception and thinking is again dopamine, a change in this transmitter system is thought to be at the basis of schizophrenia. All anti-schizophrenic drugs act on the dopaminagic system, as do all anti-depressant drugs act on the brain amine system.

Dopamine is also thought to be involved with another important system – the reward system. This system, situated in the hypothalamus and running forward into the frontal lobes, consists of a series of nucleii and their interconnecting fibres which, when stimulated, produce a pleasant feeling. Rats or cats with electrodes implanted in these areas will spend all their time stimulating themselves, sometimes never eating or drinking until they die of starvation. A similar system also exists in man and, when it is stimulated, feelings of pleasure, relaxation, even ecstasy, have been known to occur.

Now an important point to understand is the following. When any system is activated, then the degree of activation will depend on the neurotransmitter balance at that time. Brain systems can usually be triggered either by external perceptions from the outside world or from internally by the process of thinking. In either case the neurotransmitter balance within that system will be altered. Now, anger and angry thoughts have been shown to affect the brain amine balance and so affect the chemistry underlying mood. Conversely, changes in the chemistry underlying mood affects the quality and emotional tone of the thoughts we think. Thus there is a close relationship between the two. Most esoteric disciplines contain practices which limit anger or negative emotions, although it has not yet been scientifically shown, it can be predicted that the observation of these practices by the devotee will result in the normalisation of brain chemistry. Those systems underlying mood will be held stable and it is possible that the functional stability of these systems is required as a precursor to the mystical experience. Thus the brain is a highly sophisticated and delicate mechanism, any strong emotion particularly negative is liable to alter its chemistry and so limit its functioning. It is therefore not surprising that all religions have many rules relating to the devotees' behaviour and that there are codes of practice which limit their involvement with the world and teach them how to remain uninvolved with the rough and tumble of everyday life.

Thus changes in brain chemistry can be seen to be responsible for alterations in mood and cognition, but what are the brain processes which underlie perception' To gain a further understanding of this, it is necessary to return to the level of the nerve cell. The brain contains over one hundred thousand million cells, the majority situated in the cerebral cortex which, when unrolled, is a sheet some 2,000 sq cm in area and about 3 mm in thickness. It is made up of many different sizes and functions, all widely interconnected by excitatory and inhibitory synapses.

Each cell makes contact with hundreds or even several hundreds of other cells. When one cell discharges, its effects rapidly spread to other cells via its axon to the dendritic tree of other cells. At the point of contact of the dendrites on other nerve cells, a momentary activation or inhibition of that cell takes place, maybe over a hundred such excitatory impulses are simultaneously required before the cell is caused to discharge. If one accepts that the time taken for an impulse to travel from cell to cell is one millisecond or a thousandth of a second, then within the space of half to one second the activity will have spread very widely so that each neuron is affecting and being affected by thousands of others. Thus the concept is of a wave front of neural activity spreading out and sweeping through the cells of the cortex; it is this activity which is the raw substance of consciousness. Sherrington with his gift of poetry, in his book `Man on his Nature' (1940) describes it as the workings of the enchanted loom weaving 'dissolving pattern, always a meaningful pattern though never an abiding one; a shifting harmony of sub-patterns.'

What are the main features of these patterns which allow consciousness to arise' It has been known for many years that stimulation of the cerebral cortex by weak electric currents during the course of neurosurgical operations when patients have been allowed to regain consciousness can produce simple sensations. Flashes of light arise from stimulation of the visual cortex, buzzes from the auditory cortex and crude tinglings from the sensory cortex. All these sensations are elementary and simple. No complex sensations arise except when one special area of the brain is stimulated and that is in the temporal lobe. You will remember that this lobe contains structures which are associated with the filing and recall of memories. Stimulation of this area can give recall to vivid fragments of memory like the recall of a sequence from childhood at a children's party. These experiences are well formed and detailed and conflict sharply with those which arise from stimulation of other brain areas. What clearly has occurred with stimulation of the temporal lobe is that the recall memory circuits have been triggered and a memory has been relived.

Another clue to how conscious experience arises in the cortex comes from a study carried out by Libet in 1966. In the paper which he published entitled 'Brain Stimulation and the Threshold of Conscious Experience', he showed that after the stimulation current had started to flow a time interval of nearly a quarter of a second passed before any sensation appeared in consciousness. What had been happening during that time' He concluded that a wave of excitation had been spreading out from the point of stimulation and that it was not possible for a sensation to arise in consciousness until a critical number of cells had been stimulated. Assuming that about a thousandth of a second is the transmission time between cells and that each cell only stimulates two others, then about two hundred serial transmissions will have occurred in this time and huge numbers of cells will have become involved in the wave of excitation spreading out from the stimulus site (2,200). This observation leads to the idea that, for conscious experiences to arise, large numbers of brain cells must be involved in the process, but not only must large numbers be involved – the structure of the pattern of the discharge must be highly organised. Poor organisation leads to simple sensations, buzzes and flashes, etc; highly organized patterns of neural transmission lead to the formation in consciousness of the complex and beautiful world we all know so well.

But if the transmission through the cortex of neural patterns gives rise to conscious sensations, then what makes these sensations different' Why do we `hear' with the auditory cortex; `see' with the visual cortex, etc.' It would seem that the quality of the sensations which arise in consciousness depend on the structure of the underlying cortex. Evidence for this comes from the occurrence of synaesthaesia.

Synaesthaesia is the appearance in one sensory modality of activity generated in another. The commonest form of synaesthaesia is colour-hearing. In this form, if a person hears a musical note he will at the same time see a particular and specific colour. In the seventeenth century Kircher spoke of sounds as the 'Ape of Light' saying that everything visible can be made audible, just as everything which the ear perceives can also be perceived by the eye. Synaesthaesia is thought to occur in about 12.00% of the population. Scriabin the composer had this ability and used it in `Prometheus the Poem of Fire', where he devised a special colour scale notation.

Schultze (1912) reports a case of tertiary sensations coupled with music. A man of thirty, since the age of ten reported his colour hearing to be associated with taste. Instrumental music produced an image first of taste, then of colour, as if the stimulus 'went from the ear through the mouth to the eye'. Minor chords had a hard, bitter taste, major chords one that was sweet and pleasurable. After listening to music for any length of time, he would feel `full up'.

There are two explanations for the phenomena of synaesthaesia – the first, with which we need not concern ourselves, says that sound and colour come to be associated by learning. Undoubtedly in a large number of cases this is so, but it is of no real interest as no special explanation of perception results from it. The second idea is crucial to understanding how perception may function. Hayek (1962) gives a good review of the idea that there is a basic perceptional experience which becomes differentiated only as it develops along the channels of the different special senses but it also represents a unity which underpins them all. This second concept fits with the idea that we have been examining that the basic substance of experience is the neural code but that the structure of the brain provides the interpretation of consciousness. Thus it would appear that structure, the actual form of the cerebral cortex, is in part responsible for the particular form that sensations appearing in consciousness take.

This fact may provide an explanation to the mystical experience of unity. The feeling of unity may simply be due to changes in mood as it can easily be explained by changes in those systems which subserve emotion and feeling and which we briefly mentioned earlier on. However, there may also be changes in perceptions when the input from one sensory modality overflows into many others. In these cases, synaesthaesia may take place and sounds, objects and feeling may all blend into a unified whole. The golden haze seen after the mystical experience has receded has some of the properties expected of synaesthaesia, The transsensate phenomena or experiences which go beyond and are different from the usual sensory experiences of ordinary life can also in part be interpreted in this way. For example, the flame coloured light which is frequently mentioned surrounding the subject at the time of his illumination is usually associated with sensory feelings which are difficult to describe, the whole being seen as a sensory unity. Thus the occurrence of synaesthaesia suggests an explanation of some of the features of the mystical experience. For synaesthaesia to occur, it has to be postulated that the level of brain activation has to change in such a way that information flow throughout the brain, especially the sensory processing areas, is altered so as to allow an entirely new world to be synthesised. The main characteristic of this new world would then be unity.

Brain structure is also important in other circumstances when fragments of the mystical experience can be made to appear. Drugs such as LSD can produce very wide experiences, feelings of unity, universal love, vivid hallucinations, etc. Now a scientific study recently carried out by K Siegal (1977) into the changes in perception which occur to different people after they had taken LSD showed a remarkable agreement between the subjects involved. The actual patterns seen during the experience had the same basic form for all the people taking part. Now this could be because all members of the group shared a common culture but K Siegal showed that this effect was independent of culture and that, much more likely, it was due to a similarity in brain structure between individuals. This suggests that, even in people who have never had a wide mystical experience, the possibility that they will exists because of the way the human brain is made. So the idea that the potential for the full mystical experience is very widely distributed throughout mankind rests on a sound scientific fact. The very presence of this potential should spur on groups of educationalists to find the key, so that the next generation of children has a greater chance of becoming enlightened.

We have discussed brain functioning and we have related some of these aspects to the generation of the mystical experience; but are there areas within the brain which are thought to be even more closely linked with religious experience' Well, the answer to this is yes – so I would now like to go a little further into the experiences which have been recorded by people who have had lesions in the temporal lobe of the brain. You may remember earlier we were discussing the structures deep in the temporal lobe of the brain, the hippocampus and the amygdala. Some people unfortunately damage these structures early in life and develop temporal lobe epilepsy. In temporal lobe epilepsy the discharge can begin in these structures and then radiate out to involve the rest of the brain. If the discharge remains confined to the temporal lobe, then the patient has a temporal lobe type of attack in which he may not become unconscious but may experience changes in emotion, cognition and body image. Feelings of fear are very common and of such intensity that the sufferer feels that he is going to die. Feelings of ecstasy are uncommon but they do occur, in fact about 4% of all temporal lobe auras which have an emotional content are positive in quality. Some auras have the quality of a mystical experience but these are much rarer. Indeed, epilepsy and mysticism have frequently been linked together in the past and not without good reason, as has been shown by the present. Again some of the more recent evidence comes from temporal lobe stimulation during neurosurgical procedures when the patient has been allowed to regain consciousness on the operating table. Stimulation of the deep temporal lobe structures can produce feelings of calmness and satisfaction, occasionally, however, feelings of ecstasy have been evoked.

Patients with temporal lobe epilepsy are said to have particular personalities by Dr Gershwind of Boston, although many of us would not entirely agree. Dr Gershwind describes a syndrome in which the patients are said to show hypergraphia, that is they are `journalists' or write poetry, certainly they love words. They show excessive religiosity and a concern for all the more weighty of the philosophical ideas with which they endlessly play. Finally they are subject to deep religious experiences. I have certainly had several patients who have shown this. One I remember had his first experience when hearing a particularly enchanting clock chime. Suddenly the world changed; it became brighter and clearer, it was suffused by an intense white light. Feelings of love and unity poured into the soul of my patient as he stood transfixed in the certainty that we are all a unity, that the universe is ordered and that all is destined from the source of universal love. The feeling continued after the clock stopped chiming but then slowly died away. This experience has been repeated on a number of occasions. X-Ray examination of his brain showed him to have damaged one temporal lobe, probably at birth. There was little doubt that abnormal electrical activity was arising from that damaged area and that when it did the patient's mystical experience arose. Many instances can be quoted from the literature. The author and epileptic Dostoyevsky is an excellent example. In 'The Idiot', Prince Michkin gives an excellent account of an ecstatic state during the aura preceding an attack. Dewhurst and Beard (1970) give an account of ecstatic states and sudden religious conversions in six cases of temporal lobe epilepsy, taken from the epilepsy clinic records at the Maudsley and Queen Square Hospitals. All the cases had evidence of temporal lobe pathology and temporal lobe seizures. Sedman (1966), in a study describing epileptic experiences, mentions states of ecstasy in which the subject sees the Heavens open, hears God speaking and even feels himself transfigured. Various authors looking for the physical to explain the mystical have suggested that many of the more well-known mystics could be epileptic. St Paul is an obvious candidate with his sudden fall, visual and auditory hallucinations with photism and transient blindness. Bryant (1953) is the most recent author putting forward this point of view. St Teresa of Avila (1515-1583) with her visions, chronic headaches and transient losses of consciousness is said to have suffered from temporal lobe epilepsy, as is St Teresa of Lisieux (1873-1897) who is said to have experienced a series of mystical states including ecstatic celestial visions. Epilepsy has also been diagnosed as probably present in three other Christian Mystics – St Catherine of Genoe (1447-1510), Mme Guyon (1648-1717) and St Marguerite Marie (1647-1690). Despite these examples, religious experience and epilepsy is rare and most of the large surveys of populations of epileptics fail to find even a single example. What is important, however, is that it does occur, is usually associated with temporal lobe pathology and is associated with the onset of the ictal discharge. This must mean that during the discharge a brain structure or structures is stimulated to produce an experience which has the qualities of mystical experience and that these probably reside within the temporal lobe or are associated with its central connections.

There is little doubt, therefore that there exists within the brain, and probably within the temporal lobe and its associated central connections, a system which, when activated either naturally or by esoteric practices, or spontaneously, or on the operating table by direct stimulation or by the ictal discharges of epilepsy, can give rise to the mystical experience. It must be clearly understood that I am not saying that mystical experience is in any way pathological; indeed, my introduction showed how widespread in the population it is. What I am saying is that there are structures within the brain which, when stimulated either 'normally' or pathologically, will give rise to the experience.

The temporal lobe is ideally suited to mediate such an experience and it is here that the feeling `I', the feeling of certainty or strangeness and the feelings of emotion all come together and are created. These structures within the temporal lobe are probably involved in the spontaneous mystical experience. The feelings of certainty, rightness and self-validation of the experience are also likely to arise as part of temporal lobe activation.

We have now spent some time looking at the brain and its functioning and have seen both structure and the pattern of stimulation is important. How then can we understand the pattern of brain activity which is most likely to generate the mystical experience' Are there specific features about brain activity which can easily be modified by external procedures' This question leads directly on to the `stream of consciousness' of a normal person and how it is maintained and modified throughout the day. The day is only two thirds of man's life, at least twenty years or the other third are spent asleep. So sleeping and waking must be considered especially as the cosmic experience usually takes place in the evening or during the night when people awake from sleep into it. However, before discussing the sleep wake cycle, it is necessary to take a further and closer look at the functioning of the cerebral cortex.

As many of you already know, the cerebral cortex is divided into two hemispheres, a dominant hemisphere dealing primarily with the speech functions, the left hemisphere is right-handed people and the minor, or non-dominant, hemisphere, the right, in left-handed people. Both the hemispheres have specialist as well as general functions. Both hemispheres are concerned with voluntary movement, hearing, sensation and vision. The dominant hemisphere, or the left, deals with speech, mathematics, verbal memory and reading. This emphasis on the semantic and the linear has given rise to the idea that scientific linear deductive thinking derives from this hemisphere. Analysis in time is also thought to originate on the left side. An even wider application of the idea suggests that western culture with its emphasis on print, logical thinking, and a linearly orientated society is mainly a left hemisphere society.

The right, or non-dominant, hemisphere is thought to have only rudimentary ability for speech and to be mainly concerned with the understanding of the visuaspatial world. What it does is to handle the relationships of objects in space. Visua-spatial memory, musical appreciation and certain aspects of orientation are all predominantly right hemisphere functions. These ideas have been expanded into suggesting that the right hemisphere is involved with wholes; it is concerned with holistic thinking. The eastern culture, with its emphasis on the whole, is seen as a right hemisphere culture. The right hemisphere is said to deal with the integration of time. The right hemisphere is said to be intuitive while the left is logical.

Now these ideas, although finding more and more support from popular thinkers, are now falling out of fashion amongst the scientific community. The emphasis is no longer on division but more on synthesis. The brain is seen to function as a whole rather than as two separate hemispheres. For example, it has recently been shown that about 4% of people who are right-handed have their speech functions in their right-hemisphere. A much larger group has a bilateral representation of speech. Thus, although the idea of a division of functions between the hemispheres was attractive, it is now recognised that the brain functions best when it can synthesise the activity of both hemispheres into a unified whole. It must be remembered that both hemispheres are richly interconnected and that in real life situations the brain acts as a whole and not in parts. Further evidence is accumulating that the brain does act as a whole as there are several tests which can be given to people, the results of which show that in normal life both hemispheres are working in an integrated way and that the dissimilarities of functioning are more the realm of the philosopher than of the psychologist.

However, having made the plea for unity, there are still differences which are striking. After head injury, damage to the left hemisphere is more likely to result in the development of a neurotic illness than is damage to the right. Also damage to the left hemisphere is more likely to result in a schizophrenic illness. Damage to the right hemisphere is associated with a depression or an emotional illness. There is also a difference in the warning that subjects get before a temporal lobe seizure such feelings as Déjà vu being commonest with lesions on the right side.

Thus the brain should be viewed as a whole and the evidence suggests that during the mystical experience new patterns of neural activity affecting both hemispheres occur and that the experience arises from this unity of the two halves. Perhaps the mystical experience can be induced by procedures which tend to bring the hemispheres into balance. Sensory deprivation, drowsiness and Mantro-meditation are examples.

We must now return to the question, what mechanism is it that controls the brain throughout the twenty-four hour day' There is now considerable data available about the twenty-four hour cycle in man. We are at our lowest ebb at 2 a.m., we slowly alert throughout the early morning and morning until we are at our first peak at about 12 midday. We then dip down until 3 p.m., reach our second peak at about 9 p.m. and then decline until 2 a.m. This rest/alertness cycle goes on underneath all our day and night-time activity and is to a certain extent independent of them. However, it does mean that the possibilities that we have for physical and mental functioning alter throughout the twenty-four hours. For example, take a simple task like pressing a button as quickly as possible after hearing a click. The time we take is very sensitive to the time of day when we perform the test. Our mental functioning is also very sensitive to the time of day. The results on mental arithmetic tests are particularly dependent on the time of day when the test was given. Thus both our mental and physical functioning is not the unity that we think it is as we are very dependent on underlying body cycles. These cycles will structure both our mental and physical life.

Even the way we move, our body position and whether we are sitting, lying or walking, will affect our stream of consciousness and our thought content. A recent study by K Pope (1978) has shown that the content of consciousness, e.g. the number of thoughts and the length of time we stay with one topic, is dependent on the position the body is in. Walking shows fewest thoughts and lying has more, sitting is halfway between lying and walking. It is not surprising, therefore, that many of the esoteric techniques aimed at altering consciousness have precise instructions as to the body posture which much be maintained during the period of time that they are being carried out.

Besides the rest activity cycle and body posture, another mechanism which alters cerebral functioning has been discovered. The scientific evidence is not yet watertight but there are sufficient pointers to suggest that it may be so and thus it is important to mention. To understand this new idea it is necessary to have a clear idea about the structure and classification of sleep. If EEG electrodes are placed on a subject's head and around his eyes and the subject is then instructed to go to sleep, a set sequence of events ensues which can be monitored by the EEG recording. As the drowsy state supervenes and the subject drifts off into light sleep, his brain rhythms change from the alert alpha patterns to become dominated by the theta activity. As the subject's sleep deepens, the EEG rhythms continue to slow until at the deepest phase of sleep, stage four, the record is dominated by high voltage delta waves. It usually takes about ninety minutes from sleep onset to arrive at this point. This whole phase of sleep is called slow wave sleep, because the EEG rhythms slow. Abnormalities found in this phase of sleep are sleep walking, eneuresis and night terrors in children. If awakened from it, the subject takes about ten minutes to come round, feeling lethargic, lazy and unwilling to rise, a feeling I'm sure that most of us recognise only too well. Rather more important than this is the nature of the dreams that occur in slow wave sleep. The dreams are mainly kinaesthetic and verbal. It has been suggested by Professor Broughton working in Canada that during slow wave sleep the left or dominant hemisphere of the brain is mainly activated.

After ninety minutes the brain rhythms change: they become desynchronized and return to a mixture of light sleep and the waking pattern. However, during this period the channels recording activity from the eyes show rapid side to side movement of the eyes. This phase of sleep is called the Rapid Eye Movement or REM sleep. This phase of sleep is characterised by occasional nightmares and very vivid, visual, three dimensional dreams. When woken from this phase of sleep, the sleeper awakes rapidly to full consciousness, sits up and is ready to go. Dream recall is comprehensive and accurate. Professor Broughton suggests that during this time the right, or non-dominant, hemisphere is being activated. Certainly the idea of the right hemisphere being activated by REM sleep and the left by slow wave sleep would seem to be true. After ninety minutes the sleep cycle repeats itself, thus we alternate in approximately ninety-minute cycles through the night between slow wave sleep and REM sleep, or between left-hemisphere and right hemisphere activation.

Now the point of discussing sleep and the neurophysiological changes that occur during it is as follows. Professor Broughton has suggested that these ninety-minute cycles continue during the day as well as at night. Thus during the day our thinking is also influenced by which hemisphere is being activated. We go from a ninety-minute period of being rational, logical and linear into a ninety-minute period of being right hemisphere dominant or visuo-spatial, holistic and emotional. Thus the opportunity during the day for different types of cognitive work will depend on the cycle, either ventral or visuo-spatial, which is present at that time. If these cycles do truly occur and we accept the idea of alternating hemisphere dominance with its different types of thinking, then there will only be certain times during the day when you will be creative and holistic while at other times you will be logical, verbal and analytical. Possibly many esoteric methods which are designed to raise consciousness and which are repetitive are designed to take into account the varying nature of man.

Those of you who know the literature on mystical experience will be surprised that I have not mentioned some of the older theories. I refer, of course, to those ideas centered around the tropho-tropic and ergo-trophic systems, e.g. those systems which relax you and those which make you ready for action. These ideas, although useful a few years ago, have I feel been overtaken by more detailed work on the brain and so now only require to be mentioned for completeness. Other newer classifications based on EEG and its frequency bands alpha, theta and delta and skin resistance fall into the same category as there is a very poor correlation either between EEG and mental state or between skin resistance and mental state, thus these classifications are unlikely to add anything really new to the explanation of the mystical experience.

It must be remembered that EEG rhythms are quite non-specific and have no precise meaning in themselves. There are two reasons for this, the first is that the EEG is measured a long distance away in physiological terms from the surface of the cortex where the electrical waveforms are generated. This means that large groups of cells have to act together in a coherent fashion before any activity is seen on the surface of the scalp. It is estimated that at least 6 sq cms of cortex has to be activated before the cerebral rhythms are transmissible through the skull. Thus within this area many alpha and theta rhythms will be generated and what appears at the scalp is only a summated spatial average. Secondly, it is impossible to give a precise meaning to any particular rhythm. For example, theta activity is seen when you are drowsy, in REM sleep, after taking many types of drugs including alcohol, after head injury, with many types of epilepsy, during childhood, with raised intercranial pressure due to a tumour, after viral infections and some people just have a high level of theta activity anyway. It cannot be said to be related particularly to creativity or to any specific mental state. As with theta activity, so also with alpha activity; it is certainly seen during relaxation but also in the deepest coma just prior to death. Cerebral rhythms may correlate with mental state but often they do not.

So in summary the mystical experience appears to be an emergent property of brain functioning. In part, it is dependent on brain structure and in part on the activation of several systems within the brain, particularly the temporal lobe and mid brain. Neurotransmitter systems can easily be modified by esoteric techniques and different patterns of thinking. There are natural cycles within the brain which alter its activity throughout the day on a rhythmic basis. The change that modification of all these systems brings about in the neurotransmitter balance allows new patterns of cerebral activity to arise, some of these are without doubt the basis of the mystical experience.

I would like to end with the thought that the change in brain functioning can be a source of inspiration among creative artists, as is shown in this extract from the autobiography of the composer Richard Wagner ('My Life' vol. 2, p. 603, London 1911):

'After a night spent in fever and sleeplessness, I forced myself to take a long tramp the next day through the hilly country, which was covered with pine woods. It all looked dreary and desolate, and I could not think what I should do there. Returning in the afternoon, I stretched myself, dead tired, on a hard couch, awaiting the long-desired hour of sleep. It did not come; but I fell into a kind of somnolent state, in which I suddenly felt as though I were sinking in swiftly flowing water. The rushing sound formed itself in my brain into a musical sound, the chord of E flat major, which continually re-echoed in broken forms: these broken chords seemed to be melodic passages of increasing motion, yet the pure triad of E flat major never changed, but seemed by its continuance to impart infinite significance to the element in which I was sinking. I awoke in sudden terror from my doze, feeling as though the waves were rushing high above my head. I at once recognised that the orchestral overture to the `Rheingold', which must long have lain latent within me, though it had been unable to find definite form, had at last been revealed to me. I then quickly realised my own nature; the stream of life was not to flow to me from without, but from within.'


Copyright: Dr Peter Fenwick, 1980

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