response. One pathway leads to the neo cortex, the conscious, thinking part of the mind; the part that explains in detail what is happening – for example, this person is talking to me about a controversial topic. It searches through the stored knowledge for such a thing happening in the past. Stored memories can either come from the hippocampus, which searches through long-term memory banks to make sense of a situation, or the amygdala, which holds emotional information and memories. There is a ‘dialogue’ about the information and if the brain perceives that a situation calls for an emotional reaction, the amygdale quickly and automatically signals what it perceives to be the appropriate emotional response. In this instance, if you were to have an emotional tie with the topic being discussed then you may react, for example, with apprehension or anger.
However, there is a second route to the amygdala, a much quicker one that can be more useful in times of crisis. With this pathway, the information comes straight from the thalamus to the frontal cortex and amygdala and tells you that you should ACT NOW THINK LATER. This clearly makes greater sense as a survival mechanism, as we don’t often have time to have a dialogue with ourselves when confronted with a very real threat, such as an oncoming bus.
The amygdala is the emotional regulator – it decides how much emotional impact each thought carries. Whilst this is excellent in a situation that calls for an instant response, i.e. removal of oneself from path of oncoming bus, there are times when the amygdala can produce completely unnecessary responses that trigger ongoing anxiety. This process, referred to as ‘kindling’, occurs when repeated stimulus encourage the neurons in the brain to fire excessively, even when the stimulus is not potentially dangerous (see Sensitization, page 61). This response can cause havoc, as stress hormones are constantly pumped into the body, affecting all its major systems – the cardiovascular system, the endocrine system and the elimination system.
We can see that some people are naturally more reactionary and will quickly respond to an experience with fear and anxiety, while others are able to think a little before responding. However, the point is that we can make choices and as long as the perceived threat is less frightening than imagined then, through the use of language and other strategies, you can change your attitude or perception to dissipate a situation. In contrast, if you continue to repeat the response of reacting with fear when it isn’t warranted, the result can often be a more permanent state of arousal and higher levels of anxiety.
The Autonomic Nervous System
There is very much a physical reality to our anxiety levels. Anxious thoughts create high states of arousal that have an effect on the natural mechanisms of the body. As you read over the following section think about your own experience and the mixture of physiological responses that occur as a result of your anxiety.
The autonomic nervous system regulates our involuntary bodily functions – i.e. those we are unconscious of. It is divided into two systems that work in opposition to each other – the sympathetic and the parasympathetic nervous systems.
The Sympathetic Nervous System
One of the prime objectives of the sympathetic system is to do whatever is necessary to mobilize the body to handle danger. It is the chief mediator of the body’s immediate alarm reaction. Sympathetic nerves originate from cells in the spinal chord and branch out to the rest of the body’s organs and tissue sites.
If the amygdala senses trouble, it sends a message to the hypothalamus, a vital part of the sympathetic nervous system. This small but powerful gland is the link between the autonomic nervous system and other endocrine glands (glands that secrete hormones directly into the bloodstream). The hypothalamus is the controller of the involuntary functions of the body, regulating your digestive system, respiratory system, endocrine system and reproductive system. It regulates the hormones involved in governing peristalsis (the natural movement of the intestinal tract), breathing and balance, as well as the heart rate, blood pressure and temperature.
In event of a threat, the hypothalamus relays alarm to the pituitary, another ‘master’ gland, and the pituitary then tells the other glands what to do – its job is therefore to help produce the hormones that are needed to respond to different situations.
The Three Stages of the Stress Response
The sympathetic changes that take place in response to stimulus are referred to as the stress response. This response was discovered by Canadian endocrinologist Hans Seyle, who demonstrated that the body reacts in the same way to a challenging situation irrespective of whether it is a loud bang, a charging bull, or an extremely pressing deadline.
Selye suggested that there are three phases to the stress response. The first stage is the alarm reaction – your reaction to a given challenge or threat. In response to a stressful event, the pituitary signals the adrenal glands – a small pair of glands that sit at the top of your kidneys – to release the stress hormones adrenaline, noradrenaline and cortisol. Adrenaline and noradrenaline prepare the body to deal with certain conditions and are excreted in times of fear, danger or sexual excitement.
The Effects of Adrenaline and Noradrenaline
If the threat is brief and can be resolved quickly then the parasympathetic system will kick in to reduce stress levels and return the body to normal.
However, if stress is ongoing, you are likely to reach the second stage – resistance. This is when stress becomes detrimental to our health. When stress is ongoing, the result is excessive and prolonged release of cortisol.
Cortisol
Cortisol plays an important part in the stress response and is a key hormone in many other ways – it maintains resistance to such things as trauma, infections and temperature extremes; it assists in the conversion of carbohydrate to glycogen;
