Page 82 - How It Works - Book Of Amazing Answers To Curious Questions, Volume 05-15

What is anxiety?

How our brains trigger a fight or fl ight response

nxiety affects a huge number of people When we become anxious our fight or fl ight

and can be so severe that it stops many response is triggered, causing our bodies to

Asufferers from leaving their homes or flood with epinephrine (adrenaline),
doing their jobs. In the US, over 40 million norepinephrine (noradrenaline) and cortisol,

people aged 18 or over endure an anxiety which help increase your reflexes and reaction
related disorder, while in the UK one in 20 speed. Your body prepares itself to deal with
people are affected. Some researchers believe danger by increasing the heart rate, pumping
that modern day technology has infl uenced the more blood to the muscles and by getting the
rise of anxiety related conditions; we are lungs to hyperventilate.
constantly on high alert with texts, emails, At the same time, the brain stops thinking
social media and news updates. about pleasurable things, making sure that all
Anxiety is a natural human response that of its focus is on identifying potential threats. In
serves a purpose. From a biological point of extreme cases, the body will respond to
view, it functions to create a heightened sense anxiety by emptying the digestive tract by any Some people who suffer
of awareness, preparing us for potential means necessary, as this ensures that no anxiety find it hard to
leave the house
threats. In a way, it’s nature’s panic button. energy is wasted on digestion.

Cortex
How your brain reacts Once the amygdala and
The body’s primal response hippocampus have received a
to danger can be triggered stimulus, the cortex’s role is to

by non-threatening situations find out what’s caused the fear
response. Once the perceived
danger is over, a section of the
prefrontal cortex signals the
amygdala to cease its activity.
Thalamus It is vital to turning off anxiety.
Visual and auditory stimuli are fi rst
processed by the thalamus which
filters the incoming information

and sends it to the areas where it Locus caeruleus
can be interpreted.
This area of the brain stem is
triggered by the amygdala to
initiate the physiological
responses to anxiety or stress,
such as an increase in heart
Two paths rate and pupil dilation.
A startling signal such as a sudden
loud noise will be sent from the
thalamus via two paths: one travels
directly to the amygdala - where it
can quickly initiate the fear
response - and the other passes
through the cortex to be processed Hippocampus
more thoroughly. The hippocampus is the brain’s
memory centre, responsible
for encoding any threatening
events that we experience in life
Stria terminalis into long-term memories.
The bed nucleus of the stria
terminalis (BNST) is responsible
for maintaining fear once this
emotion has been stimulated by
the amygdala, leading to
longer-term feelings of anxiety.
Amygdala
This is where the fear response is
triggered. The amygdala can quickly
put your body on high alert, and
research suggests that if this area of © Alamy; Thinkstock
the brain is overactive, it may cause
an anxiety disorder.

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