Whenever we come across any traumatic or stressful event it leaves an everlasting impression on us. The brain can never erase what was registered in the past. Most people would often have wondered how extraordinary it would be if we had a mechanism that stopped us from getting fearful after a certain point.
Researchers from the University of Exeter Medical School have for the first time identified the mechanism that protects us from developing uncontrollable fear.
According to what they have found, our brains have an extraordinary capacity to adapt to changing environments – experts call this 'plasticity'. Plasticity protects us from developing mental disorders as the result of stress and trauma.
Researchers found that when a person goes through a stressful event the brain re-programmes certain receptors in the emotional centre of the brain, which the receptors then determine how the brain reacts to the next traumatic event.
These receptors act like a command centre, telling neurons whether they should stop or accelerate their activity.
Before a traumatic event, the receptors usually tell the neurons in the emotional centre of the brain to remain active and produce vivid emotions. However, after trauma they command these neurons to stop activating and stop producing emotions – thereby protecting us from developing uncontrollable fear.
This helps us to control our emotions, and not get too frightened and exaggerate even during mild or irrelevant fear, for example, someone who may have witnessed a road traffic accident who develops a fear of cars or someone who may have had a dog jump up on them as a child and who now panics when they see another dog.
The research team used mice in which the receptors were genetically de-activated and found that the animals developed a pathological fear in response to even mild, aversive stimuli.
The study was led by Professor Robert Pawlak of University of Exeter Medical School. He said: "The discovery that the same receptor can either awaken neurons or 'switch them off' depending on previous trauma and stress experience, adds an entirely new dimension to our knowledge of how the brain operates and emotions are formed."
Professor Pawlak added: "We are now planning to extend our study to investigate if the above mechanisms, or genetic defects of the receptor, are responsible for the development of anxiety disorders and depression in human patients. There is more work to be done, but the potential for the development of future therapies based on our findings is both exciting and intriguing."
The article has been published in the prestigious psychiatry journal Molecular Psychiatry.
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