2024-04-13 06:00:03
Fear without a real threat can harm our mental health. Neurobiologists have discovered how to block this process.
Our nervous system is designed to induce fear, an essential survival mechanism. However, in the absence of tangible threats, this fear can become detrimental to our well-being. This phenomenon is particularly worrying for people who have experienced stress severe or life or death situations, which can lead to long-term and disabling mental disorders such as post-traumatic stress disorder (TSPT).
Neurobiologists from theUniversity of California San Diego identified the biochemical modifications of brain and mapped the neural circuits at the origin of experiences of generalized fear, which are paralyzed in seemingly non-anxiogenic contexts, according to their work published in the journal Science. This discovery opens new avenues for preventing fear responses. In this study, the team examined the mouse brain, specifically the dorsal raphe in the trunk cerebral. They found that acute stress caused a change in the chemical signals of neurons from excitatory “glutamate” to inhibitory “GABA” neurotransmitters, resulting in generalized fear responses.
Digging deeper, they also observed a similar change in neurotransmitters, from glutamate to GABA, in the post-mortem brains of people who had suffered from PTSD.
Research published in Science reveals the brain biochemistry and neural circuits responsible for experiences of generalized fear.
Credit: Spitzer Lab, UC San Diego
A method was developed to stop generalized fear: before exposure to acute stress, scientists injected the dorsal raphe of mice with an adeno-associated virus (AAV) that suppresses the embarrassed responsible for the synthesis of GABA, thus preventing theacquisition widespread fear.
Additionally, immediate treatment of mice with the antidepressant fluoxetine (known as Prozac) after a stressful event prevented change in neurotransmitter and the subsequent appearance of generalized fear.
The researchers not only identified the location of neurons that changed their neurotransmitter type, but also demonstrated the connections of these neurons with the central amygdala and lateral hypothalamus, regions of the brain previously linked to the generation of other responses. of fear.
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