Does science have a way to help 'turn off' fear?

When you're scared, you feel your hair stand on end, your stomach churns, your heart pounds. Scientists recently discovered the fear "switch" in the brain and how to turn it off.

Fear can be terrifying, and strangely, also exciting, for example when you're exploring an abandoned house.

Fear is both beneficial and harmful

Essentially, fear is a beneficial emotion. However, there are times when fear causes a lot of trouble - (Photo: Shutterstock).

Essentially, fear is an incredibly useful emotion. This is an instinctive response to danger, which increases your chances of survival when the situation gets worse. However, there are times when fear causes a lot of trouble.

In cases such as anxiety disorders and stress disorders, the fear response can become inappropriate for the situation or environment around you, seriously hindering your mental health and quality of life. .

To better understand fear and how this emotion works, a research team led by neurobiologist Hui-Quan Li of the University of California San Diego (UC San Diego) mapped the changes in brain chemistry and nerve signaling in mice subjected to extreme fear. Research has even found ways to prevent fear.

The study was conducted in mice genetically engineered to express a specific transporter of the important neurotransmitter glutamate in the brain (excitatory neurotransmitter - PV), as well as the protein fluorescence in the nuclei of their brain cells, thereby allowing changes in the brain to be monitored.

The mice were given electric shocks of two different severities under specific conditions. When they return to that space two weeks later, they tend to freeze in fear.

People in severe shock also have a similar tendency to "freeze" as rats, in a different environment, indicating a generalized overreaction. Looking inside the brain, it is possible to see what drives this excessive fear response.

Specifically, the researchers looked at a brain region called the dorsal raphe , located on the brain stem of mammals. This part of the brain is responsible for regulating mood and anxiety, as well as providing significant amounts of serotonin to the forebrain. Importantly, the dorsal sulcus also plays an important role in fear learning.

In cases such as anxiety disorders and stress disorders, the fear response can become inappropriate for the situation or surroundings - Photo: Simply Psychology

How to "turn off" fear?

The team found that a severe feeling of fear turns on a "switch" in nerve cells, changing the neurotransmitter mechanism from glutamate - a neuron stimulant, to GABA - an inhibitor. nerve cell activity. 

This "switch" appears to keep the fear response on when it should be turned off or gone, producing symptoms consistent with an anxiety disorder or generalized fear.

A study of the brains of deceased people who suffered from PTSD (post-traumatic stress disorder - PV) while alive showed a similar switch from glutamate to the neurotransmitter GABA.

This finding is a starting point for finding ways to prevent the fear response . One way is to inject mice with an adeno-associated virus to inhibit the gene responsible for producing GABA. 

When the researchers trained these mice with fear stimuli, they did not develop signs of generalized fear disorder as in mice not treated with the virus. This method of prevention requires knowing in advance some of the ongoing stressors that can lead to the disorder.

However, researchers have found methods to minimize the impact of fear after the event. If treated with the common antidepressant fluoxetine immediately after the fear, neurotransmitter turnover and subsequent generalized fear are prevented.

But this treatment must take place immediately. Using medication after the neurotransmitter switch has occurred and the fear response becomes apparent is too late. Researchers say this may explain why antidepressants are often ineffective in patients with PTSD.

The findings are not yet considered a cure, but are a promising start to effective treatment. 

"We have grasped the core of how stress-induced fear occurs and the circuitry that executes this fear. Thanks to this, interventions can be more targeted and specific" , Nicholas Spitzer , a neurobiologist from UC San Diego, said.

The research was published in the journal Science .