Hypnosis is an altered state of consciousness. This is an altered state of consciousness which arises due to changes in the brain. These changes can occur naturally in some circumstances but in hypnosis they are induced with the use of specific techniques. In the hypnosis your attention is focused and narrowed. This creates the environment in which your brain can process information in a different way, and allows you to access more areas of your brain. Hypnosis is not a form of sleep, but it has a number of similarities. When you experience hypnosis you often feel extremely relaxed physically, your body may feel as though it has gone to sleep and you often keep very still. In fact you remain awake. The conscious part of the brain is turned down and the unconscious part of the brain is more active. 


Hypnosis is the state. Hypnotherapy is the approach. Hypnotherapy is a form of therapy which utilizes the state of hypnosis as its main therapeutic tool. Hypnosis leads to the significant changes in mental process. These change the way the brain processes information during the hypnosis, and can be utilized to bring about therapeutic change. Hypnosis allows you to bypass the conscious mind and the limitation of the conscious thought. Hypnosis enhances your ability to be imaginative and to process information differently. These abilities are utilized by the therapist to help you address problems successfully. Hypnosis has been used as a therapeutic tool for thousands of years but the way hypnosis works has only recently been understood from a scientific point of view. 

What does hypnosis feel like?

There is nothing magical about hypnosis, although you may find some of the affects of hypnosis magical in nature. Everyone’s experience of hypnosis is unique but there are some common aspects experienced by most people. Hypnosis involves entering an altered state of consciousness. Have you ever been so engrossed in a task, such as playing sport or reading a great novel, that you are completely unaware of what is going on around you and unaware of time passing, like you are in a zone? This is similar to the altered state experienced in hypnosis. In other ways hypnosis resembles the experience just before you drift off to sleep, where your mind wanders and you feel very relaxed, you are still aware and yet your body feels asleep. Generally in hypnosis you experience this feeling of deep relaxation, but this is paired by feeling mentally aware. There may be a feeling of detachment from the outside world; for example, in hypnosis you would still be able to hear traffic outside but it may seem distant or irrelevant. Often people experience some degree of change of sensation in their body, particularly in the limbs. You may experience a sensation of floating, of not quite being aware of your body, of feeling light. Time is often distorted too and it is common to feel that you have been in a trance for only a few moments when actually 20 minutes have passed. Alternatively you may feel you have been relaxed for half an hour and when you look at the clock only a few minutes have passed. It is a pleasant experience. 

The Brain and Hypnosis

A basic knowledge of brain functioning in relation to hypnosis allows you to understand how it can be used successfully as a therapeutic tool. Changes in the brain create the state of hypnosis and allow for processing of information in a different way. It is the reprocessing that brings about therapeutic change.

This change in brain state comes about due to changes in the autonomic nervous system. There are two main parts to the autonomic nervous system. The first is the sympathetic nervous system, which is dominant when we are aroused, stressed or threatened. Sometimes this is called the “fight or flight” response. Your heart quickens, you sweat more, and your blood pressure increases as your body prepares for action. The second is the dominant parasympathetic nervous system when your body is relaxed. In this state your heart slows down, your breathing slows and all your bodily functions decrease as your body is in a physically relaxed state. In hypnosis there is a switch to this parasympathetic dominance of the autonomic nervous system, which initiates the altered state of consciousness.

Brain Basics

The brain is the control centre of your body and mind. The human brain has evolved over millions of years but the basic human brain remains the brain of the first human evolved. The human brain also has many commonalities with animals and others mammals. The main difference is humans have a more evolved conscious brain. However, the unconscious part of the brain is, in some ways, the more important. As humans, we tend to focus on our conscious abilities and because we have the ability to think in language and communicate with words we tend to over-rely on these abilities. However, most of the processing brain goes on in the unconscious part of the brain. The brain processes the information from the external world and internal bodily states. Information travels to and from your brain and the rest of your body as nerve impulses along your spinal cord. Through this process the brain regulates conscious and unconscious body process. It is via these processes that a hypnotic state develops.


The Cerebral Cortex

The cerebral cortex is the largest part of your brain, encompassing about two–thirds of the whole brain mass, and is the most recent structure in the history of brain evolution. The cortex forms the outer layer of the brain and it has a heavily folded grey surface. It is responsible for conscious awareness of thoughts and behaviours, and producing and understanding language. The front part of the cortex, the frontal lobe, is specifically involved in the conscious awareness in decision making, emotional thought and skill movements. Behind this is the parietal being which perceives and interprets sensations like touch, temperature and pain. At the back of your brain lies the occipital lobe which is concerned with visual images. On either side are the temporal lobes which are involved in hearing and some cognitive processing. You are not aware of all the processing in the cortex as most of it remains unconscious, but conscious awareness arises from the outer layer of the brain. In hypnosis this conscious part of the brain is less active.

The cerebral cortex is split down the middle into two halves called hemispheres that are joined together and communicate with each other via a massive bundle of nerve fibres called the corpus callosum. Brain activity between the hemisphere changes in hypnosis. Increased activity between the hemispheres of the brain gives rise to some hypnotic phenomena, such as a dream-like quality of thoughts, increased visual imagery and time perception distortion.


The Limbic System

The limbic region lies deep within your brain beneath the middle of your cerebral cortex and on top of your brain stem. It governs the rest of the brain and the body. Its processes are unconscious. This part of the brain processes material before you are aware of it. The limbic system controls the level of activity in the cortex. Signals are sent to the conscious areas of your brain from the limbic region. Alterations in the limbic system are involved in producing the altered state of consciousness experienced during hypnosis. The limbic system also regulates learning, memory, attention and emotions. Changes in the limbic system during hypnosis are also critical to the therapeutic benefit of hypnosis.


Brain stem and Cerebellum

The brain stem and the cerebellum monitor most of the basic functioning of the body and are very old in evolutionary terms. They are responsible for regulating many life-support mechanisms; such as your heart rate, blood pressure, digestion, breathing and basic movement. The brain stem is essential in maintaining consciousness. It plays a pivotal role in the altered state of consciousness experienced during hypnosis.

All information relayed from the body to the brain, and vice versa, must traverse the brain stem. Pain, temperature and touch are all sensory experiences meditated via the brain stem. These are often altered during hypnosis indicating a change in brain stem activity.

The cerebellum is particularly interesting because it contains more neurons (brain cells) than the rest of the brain put together. It used to be thought that the main role of the cerebellum was to co-ordinate body movements; however, the last 20 years has seen new evidence showing the cerebellum is also critical in attention, memory, language and mental imagery. Unlike other areas of the brain which generally communicate in a two-way system the cerebellum tends to send out more signals to the rest of the brain than it receives. During hypnosis changes in the cerebellum are likely to mediate many changes in conscious awareness.


How the brain works as a whole

The brain stem and cerebellum can be viewed as the foundations. They are necessary to human life but not sufficient for human existence. The limbic region acts as the control centre of human experience. It is unconscious and mediates the activity of the cortex. The cortex allows us to be aware of our human experiences. The limbic region is the most critical part of the brain in hypnosis for two reasons. First, the hypnotic experience comes about because of the changes in the limbic system. Second, these changes mediate the therapeutic benefit of hypnosis. Hypnosis is produced by changes in the limbic system and therapeutic change comes about via processes in the limbic system, it contains many important structures including the hypothalamus, the thalamus, the amygdale, the hippocampus, the insula, the nucleus accumbens and the cingulate gyrus. These structures all communicate with each other and also with other widespread areas of the brain including the brain stem and the cortex, as well as the rest of the body.


The Hypothalamus

The hypothalamus controls much of our every day functioning. It is a small, almond-shaped structure deep within the limbic system on top of the brain stem. It links many important processes within the body. It regulates body temperature, hunger, thirst, sleep and libido. It has a role to play in emotions and also regulates the immune system.

The hypothalamus is involved in the production of the hypnotic state as it regulates the autonomic nervous system. Changes in the autonomic nervous system, from sympathetic dominance to parasympathetic dominance, are key features of hypnosis. This change is regulated by the hypothalamus and plays a major role in producing the altered state of consciousness experienced in hypnosis. The hypothalamus is also involved in the therapeutic benefits of hypnosis. Because of its pivotal role in emotional regulation as well as mind and body communication, changes in the hypothalamus allow for reprocessing during hypnotherapy.


The Thalamus

The thalamus lies just above the hypothalamus and acts as a relay station for information coming into your brain from your senses. It sends appropriate signals to other parts of the brain. It is involved in the process of inducing a hypnotic trance state. The thalamus receives less input from the senses and therefore can work in a different way. Alterations in pain perception experienced in hypnosis are also mediated by the thalamus.


The Amygdala

The amygdala is known as the fear centre of the brain and is involved in emotional processing. It is responsible for initiating the “fight or flight” response you experience when faced with danger. It interacts with the hypothalamus, hippocampus and other structures within the limbic region. During hypnosis the amygdala is less active and this contributes to changes in the autonomic nervous system. The body goes into parasympathetic dominance. Your heart slows down, your breathing slows down, and your blood pressure remains low. This produces and sustains the experience of relaxation and the ability of the mind to process thoughts and behaviours. Due to the involvement of the amygdala in emotional processing, changes in this region are also involved in the therapeutic effects of hypnotherapy.


The hippocampus

The hippocampus is a horse shoe shaped layer of cells adjacent to the amygdala. It is responsible for the processing of new memories, emotional regulation and spatial orientation. One role of the hippocampus is to keep the conscious brain attentive. This mechanism is turned down in a hypnotic state. The techniques used to induce a hypnotic state affect the activation levels in the hippocampus. This results in changes throughout the limbic system and the hippocampus appears critical in the neurological mechanism of hypnosis.

Changes in the activation of the hippocampus are involved in the heightened ability to process information in hypnosis. The hippocampus and the amygdala are closely related. Therapeutic change in emotion regulation during hypnosis is facilitated by the links between emotions and memory processed by these two structures.


The Insula

The insula is on the outer edge of the limbs region and the inner folds of the cortex. It is involved in conscious awareness. It contains special cells only found in the brains of human and great apes. The insula is involved in empathy and the ability to preconceive what an experience is going to feel like. It also processes bodily states, for example pain and temperature, and is activated when you think about these states. It is the biological basis of intuition. Along with the hypothalamus and the amygdala it influences the homeostasis of the body, including regulating the balance between the sympathetic  and parasympathetic nervous systems, and therefore involved in the production of a hypnotic state. The insula is also involved in the therapeutic process and in particular the ability to reprocess information using the imagination. The insula plays a part in immune system functioning. Many therapeutic effects experienced with hypnosis are likely to be mediated through insula.


Nucleus Accumbens

The nucleus accumbens, called the pleasure centre of the brain, is involved in reward, pleasure, laughter, sexual arousal, addiction, fear and aggression. It is also involved with what information becomes conscious. It is involved in both the altered state and therapeutic change.


The Cingulate Gyrus

Resting between the cortex and the limbic region lies the cingulate gyrus. It is situated just above the corpus callosum, the bundle of nerve fibres connecting the two hemispheres of the brain. It is involved in the suppression of cortical activity and the change from conscious to unconscious processing. It also has a wide range of emotional and cognitive functions which influence autonomic activity. It is involved in the emotional response to pain.


Brain activity and Hypnosis

During hypnosis there are changes in the electrical activity of the brain, mediated by the cingulate gyrus. These brain patterns can be measured using electroencephalography (EEG). This involves placing electrodes on the scalp to record the level of electrical activity in the brain. When we are awake and alert, talking to friends or at work, the brain is in an alert state. This is reflected in mainly BETA brain waves which are short and spiky, reflecting lots of activity going on. When we are more relaxed, watching television or listening to music for example, the brain shows slower, more gentle brain waves, called the ALPHA waves. When we are asleep the brain is in an even more relaxed state and shows DELTA waves which are much slower, apart from periods of Rapid Eye Movement (REM) sleep when the brain temporarily increases its activity. When a person is experiencing hypnosis the brain takes on a different form, which is neither awake nor asleep but is active, but relaxed. The brain in hypnosis produces THETA brain waves. This is the key hypnosis.


How does Hypnosis make the brain work at a different rate?

The techniques used in hypnosis, produce this altered state through a number of mechanisms. One of these mechanisms involves changes in the autonomic nervous system. The autonomic nervous systems governs the body’s state of balance. There are two main parts of the autonomic nervous system, namely the sympathetic nervous system, which is dominant when we are aroused, feeling stressed or threatened. At the other extreme, when your body is relaxed, the parasympathetic nervous system is dominant. In this state your heart rate slows, your breathing slows and all your bodily functions decrease as your body is in a physically relaxed state. Many techniques of hypnosis encourage parasympathetic dominance and this creates a state where your brain more easily produces ALPHA and THETA patterns, which reflect this deeply relaxed state.

The homeostasis, or balance, of the body through the autonomic nervous system is governed by the hypothalamus in conjunction with other areas of the limbic system. The hypothalamus controls the autonomic nervous system through a pathway called the Hypothalamic Pituitary Adrenal (HPA) axis. The hypothalamus sends chemical messages to the pituitary gland, a small structure deep within the brain, which controls the release of hormones. These messages travel down the body to the adrenal glands, situated on top of the kidneys. The adrenal glands then control the level of stress hormones in the body which in turn activates the sympathetic nervous system, which regulates the “fight or flight” response.


The HPA axis role in hypnosis

When someone enters into hypnosis they become more relaxed, which sends signals to the HPA axis that there is no danger and it is safe to send messages to the body to go into parasympathetic dominance. This encourages further relaxation and even deeper levels of physical relaxation similar to those which occur during sleep, but the advantage is that the person is still awake and has a level of conscious awareness.


How the mind affects the body

In the past the mind and body were viewed as separate entities according to western philosophy, thoughts were not considered able to affect the body. But with the development of scientific evidence, it is now well established that mind, thoughts, beliefs and emotions all affect the physical body. Every thought has a neurological consequence. Thoughts affect what is going on in the brain and therefore affect responses of the whole body.


Unconscious and the conscious processing

The brain changes what takes place during hypnosis to allow you to access parts of your mind that are otherwise unconscious and inaccessible. That part of the brain which allows you to be aware of your conscious thought is just the tip of the iceberg. The unconscious part of the brain is the machine working away behind the scenes. As an example, much of what we see and hear is not consciously registered by our brains.  It is processed unconsciously, and then some of it reaches conscious awareness.