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Frozen: Neuroscientists have discovered exactly how the brain links its survival circuits to the spinal cord, causing the body to freeze

Fear is primitive. In the wild, it instinctively protects animals from predators - but for humans, the emotion can be far more complex.  

Fear can trigger the 'fight or flight' response to raise the heart rate, sharpen the senses and provide access to huge amounts of energy in order to cope with threats to survival.

At times, the threat is so intense it can cause a 'freeze' response. This could be interpreted as the brain being overwhelmed, or it may have evolved as a way of keeping still to hide from predators.

Now neuroscientists have discovered exactly how the brain links its survival circuits to the spinal cord, causing the body to freeze in the face of danger.  

The discovery could help develop effective treatments for emotional disorders such as anxiety, panic attacks and phobias.  

Scientists know that memories are learned and stored in a small structure in the brain known as the amygdala.  

Any disturbing event activates neurons in the lateral and then central portions of the amygdala.  

The signals are then communicated internally, passing from one group of neurons to the next. From there, they reach neurons in the brainstem, the action centre for fear responses.

Researchers believe something known as the periaqueductal gray (PAG) can trigger responses such as freezing, a high heart rate, increase in blood pressure and the desire for flight or fight. 

The discovery could help develop effective treatments for emotional disorders such as anxiety, panic attacks and phobias. Nicole Kidman (pictured) is known to suffer from panic attacks

The study by Bristol University has discovered a brain pathway leading from the PAG to a part of the cerebellum – a region of the brain that controls motion - named the pyramis.  

The research went on to show that the pyramis is involved in generating freezing behaviour when someone faces danger.  

'There is a growing consensus that understanding the neural circuits underlying fear behaviour is a fundamental step towards developing effective treatments for behavioural changes associated with emotional disorders,' said Dr Stella Koutsikou at the University of Bristol.  

Professor Bridget Lumb, Professor of Systems Neuroscience, added: 'Our work introduces the novel concept that the cerebellum is a promising target for therapeutic strategies to manage dysregulation of emotional states such as panic disorders and phobias.' 

Panic attack: Psychologists have said that humans have an innate response to danger that alerts our bodies before our cognitive brain has processed the threat