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An Anatomy of Fear

Fear is one of the best understood emotions in terms of neuroscience. Fear in humans is largely controlled by the amygdala, a small almond shaped part of the brain in the limbic ring at the top of the brain stem. The amygdala acts as an alarm system for the body, capable of flooding the brain and body with adrenaline, noradrenaline and other hormones, activating our instinctive fight or flight mechanisms in under a second.

The oldest and most primitive part of the human brain is the brain stem, which is sometimes known as the lizard brain. The brain stem is at the top of the spinal cord and regulates the body’s basic functions: breathing, the metabolism and basic movements. This portion of the brain cannot be said to “think” in a meaningful way, rather it has a set of preprogramed reactions. The next oldest part of the brain is the olfactory bulb, which analyses tastes and smells, making simple distinctions, good or bad, eat or don’t. From this core area the other emotional centres, or limbic system, developed. The limbic system forms a ring around the brain stem. As mammals developed, the limbic system added a wider range of emotions and two essential survival skills: learning and memory. Then, around a hundred million years ago mammals went on to add a third layer to the brain – the neocortex. This is the area of the brain that actually “thinks”. In humans this area of the brain is more developed than other mammals, but, importantly, it can still be overridden by the older areas of the brain, particularly in matters relating to survival.[i]

The amygdala monitors incoming information from the senses and determines basic emotional responses such as pleasure or fear. It is linked to many parts of the brain so that it can receive many kinds of sensory information. Its lateral nucleus receives visual and auditory information from the thalamus, the visual and auditory cortices. The corticomedial area receives messages about smells from the olfactory bulb, while the central area receives messages about tastes.

The amygdala is also connected to almost every other major part of the brain. From the central and medial areas it connects with the hypothalamus, which produces CRH (corticotropin-releasing hormone) and initiates the cascade of hormones that produce the fight or flight response. The amygdala’s basal area links to the corpus striatum, and the brains system for movement. The basolateral area of the amygdala connects to the cingulate cortex and ‘central grey’, which control the skeletal muscles. The central nucleus of the amygdala connects to the medulla and the autonomic nervous system, which controls a wide array of functions from breathing and heart rate through to muscular activity and digestion. Another connection links the amygdala to the locus ceruleus in the brainstem, which manufactures noradrenaline (or norepinephrine).

In practical terms this is how fear works: You see or hear something that disturbs you.

First, the eye or the ear take light or sound waves and convert them to sensory signals that are sent to the thalamus. From the thalamus the signal is split. One part of the signal crosses a single synapse into the amygdala and the other is routed to the neocortex. Visual information goes to the visual cortex and sound information goes to the auditory cortex in the temporal lobe. The brain parallel processes the information. While the thinking part of the brain is trying to work out what the sight or sound is, the amygdala runs a simple analysis of the sound in the hippocampus (which has a rudimentary memory system). This parallel processing is efficient in life and death situations as the amygdala can trigger the start of an emotional response before the neocortex has worked out what is happening.

When the more sophisticated analysis comes in from the neocortex, the amygdala may stand down the alert or trigger further alarm. Its central area activates the hypothalamus, which secretes CRH and initiates the fight or flight response. The central nucleus also connects to the medulla and the autonomic nervous system, which stimulates the cardio vascular system, increasing breathing and heart rates.  The amygdala causes the locus ceruleus to release noradrenaline (or norepinephrine), which spreads through the cortex, the brainstem, and the limbic system setting the brain on edge and preparing for a large reaction.

All of this will have happened unconsciously, you will not even be aware that you are frightened yet.

Second, the unconscious reactions that the amygdala has orchestrated start to enter consciousness. In the first 150 milliseconds of being startled four involuntary reactions occur: you blink, the head and torso lean forward, the elbows bend and the hands ball into fists[ii]. Another common reaction is to inhale and hold your breath. Your heart rate and blood pressure rise.

As this is going on amygdala and hippocampus trigger the release of dopamine into the brain to further increase attention. Endorphins are released into the body in anticipation of pain. Vasoconstriction occurs to minimise blood loss if you are wounded. This is a key difference to what happens during exercise. In exercise the heart rate increases and vasodilation occurs allowing more blood to be pumped faster, but in fear the increased heart rate fights against the contracting blood vessels and blood pressure sky rockets.

Third you enter a state of fear - the gut tightens, the muscles in the neck tighten, the heart races, the limbs may tremble, the muscles may freeze in place. In effect the oldest and simplest part of the brain has taken control of you and you are unlikely to be entirely rational. It is also common to experience a range of perceptual distortions. 85% of people experience diminished sound, 80% experience tunnel vision, 74% go onto ‘autopilot’, 65% experience slow motion time, 40% dissociate and 7% experience temporary paralysis.[iii]

And all of this may have happened in under a second.

While in evolutionary terms this process was invaluable for survival, in the modern times some of the effects are not so useful. Extreme stress may lead to panic attacks, phobias or simply unhelpful reactions. Part of the problem is that while we may intellectually be able to differentiate between being attacked by a sabre tooth tiger and being annoyed by the ignorance and rudeness of the person working at the next desk, physically and unconsciously we do not.

For whatever reason we are disturbed the amygdala triggers a process that begins with the release of CRF from the pituitary and ends with a flood of stress hormones, and in particular cortisol. Cortisol remains in the body for hours and if we are subjected to incident after incident the amygdala will be left increasingly sensitive and ready to initiate further panic reactions.[iv]

Under stress reactions heart rate and blood pressure rise in preparation for fight or flight and is diverted away from non-essential activities such as the brain’s higher cognitive functions. The senses are heightened and the mind is dulled. Large movements are primed and fine motor skills are reduced. For most people motor skills begin to deteriorate at a heart rate between 115 and 145 beats per minute. With training you can push this to 175 beats per minute, but beyond that you will suffer a severe deterioration of mental and physical performance.[v]

Long term, high cortisol levels have other detrimental effects. Cortisol steals resources from the memory. It makes people make more errors and makes them more distracted. Being unable to remember something that you have just read during an exam is a familiar example of the effect of high cortisol levels. In the long term high cortisol levels have been shown to atrophy the hippocampus and damage the intellect[vi]. Cortisol also affects the way that we store fat and there is a link between stress and the accumulation of visceral fat (combine that with a desk job and comfort eating and you end up with the kind of hip to waist ratio associated with diabetes, high blood pressure and coronary heart disease).

Long term exposure to high levels of endorphins also has a negative psychological affect known as anhedonia (the inability to feel pleasure) and is one of the symptoms associated with post-traumatic stress disorder (PTSD).

The impact on the autonomic nervous system can be serious too. It can lead to poor breathing patterns, dysfunction of the digestive system and so on.

But what has this to do with taijiquan? A number of things

  • The use of relaxation and breathing techniques to reduce stress and mitigate the symptoms of stress
  • More effective learning strategies for martial arts in general

Traumatic memories can remain as fixations and interfere with subsequent learning or re-learning. This is the root cause of phobias. You often see a similar, but less excessive reaction to being hit. In punching drills many people over react with movements that are too large to be effective and quite literally become rigid with tension.

The key to overcoming this is a process known as ‘fear conditioning’ or ‘stress inoculation’. This involves relearning the reactions by repeated exposure to a weakened version of the initial stressor. For taijiquan this means working slowly and softly. A punch is presented in a way that does not threaten or frighten the student, so that they can engage intellectually and practice using fine motor skills to deal with it. Then gradually the speed, weight, power and penetration of the punch can be increased, mostly staying within the student’s comfort zone, but gradually increasing the range of strikes that they feel comfortable dealing with.

Fear conditioning is cortical. The brain has to be sufficiently relaxed to engage intellectually with the exercises. The fear reaction of the amygdala does not go away. It is just that the cortex is able to suppress the fear reaction by sending messages to the amygdala that this is familiar and can be dealt with. Or when under stress the limbic system also be able to make use of the conditioned responses that have been drilled. The removal of fear is an active process that follows its own logic and timeframe.

This work requires time and patience. It takes time to acclimatise to uncomfortable situations, to recognise their pattern and logic. It takes time for it to stop being stressful. During this time useful patterns should be implanted so that in a real situation the unconscious mind will simply follow the established template rather than freezing. If you move to quickly in advancing this training you risk implanting stress reactions. These behave similarly to a micro-tear in a muscle during stretching, most of the time it doesn’t matter, but occasionally this invisible weakness may reveal itself catastrophically at a point of severe stress.

A key aspect of this training is breathing. Breathing is the key mechanism that we have to control stress. By taking control and using relaxing breathing patterns such as ‘tactical breathing’ (breathe in for a count of for, hold for four, exhale for four, hold for four) during stressful situations we help to begin a re-education process where an element of calm is juxtaposed with stress, giving an element of control. As such learning basic breathing techniques can be invaluable preparation for stressful situations and prevention for phobias and post-traumatic stress.

By starting with the heart at a lower base rate it may not reach such a high rate as to affect performance. By linking movement and breathing we can reduce the physical stress, use less energy and keep the heart rate lower during actions. Also the linking of breath and movement lets us re-gain control of the breathing and heart rate more quickly, reducing the impact of the high heart rate on performance. This is particularly useful in conditions when it is difficult to breath such as when you are winded (a temporary paralysis of the diaphragm as a result of the phrenic nerve being shocked), in such a condition you can use the mechanical movements of the body to squeeze air in and out of the body, keeping you breathing and aiding recovery.

Again, these skills need to be drilled while calm. This helps retain them while under stress. Sometimes this is referred to as muscle memory. This is also, why it is important to train the movements slowly, smoothly and correctly rather than fast incorrectly. Regular and continuous training is important as learned skills diminish, and research suggests a half-life of about six months.[vii]

Nowadays, more of us are dying from illnesses related to stress and physical inactivity than from fights or predation. The human body does not differentiate between different kinds of stress. Learning to deal with the fear of a combat situation will also give you the skills to deal with the stress of modern urban living. Learning to deal with the shock of being hit can help with the shock of an accident.

By understanding the anatomy of fear we can improve our training and make it more efficient. Taijiquan is an art of yin and yang. We need to work with both relaxation and excitement for the art to be balanced. In this sense the martial side of taijiquan is still an essential part of extending our relaxation and health skills. Anyone can be calm on a mountain top, where there is no disturbance, but few of us live on mountain tops, so the relaxation skills of combat may have a much wider value.


Glenn Gossling, January 2012


[i] Daniel Goleman, ‘Emotional Intelligence’, 1995

[ii] Bruce Siddle, ‘The impact of the sympathetic nervous system on use of force investigations’, 2011

[iii] Dave Grossman, ‘On Combat’, 2004

[iv] Daniel Goleman, ‘Working with Emotional Intelligence’, 1998

[v] Dave Grossman, ‘On Combat’, 2004

[vi] Daniel Goleman, ‘Working with Emotional Intelligence’, 1998

[vii] Dave Grossman, ‘On Combat’, 2004