• Fear is a natural emotion triggered by a perceived threat. However, it can also be a factor in fear-related mental health issues.
  • Scientists believe the biological processing of fear occurs in a part of the brain called the amygdala – although other brain regions like the thalamus and brainstem may also play a role.
  • How this process occurs isn’t fully understood, but new research shows how specific molecules in separate parts of the brain pick up and transmit threat signals to the amygdala, transforming them into fear.
  • The researchers suggest that their findings could lead to new therapies for mental health disorders related to fear, migraine and hypersensitivity disorders often experienced by people with autism.

Fear is a natural emotion in humans and animals that can help detect and respond to real or perceived danger.

When a person perceives a possible threat, biochemical reactions occur to prepare the body and mind to respond – known as the fight, flight or freeze response.

A 2016 research review explains that this fear response is processed in a region of the brain called the amygdala. Faced with a possible threat, the brain receives information from the sensory system by sight, hearing, smell and touch. Then, this information activates parts of the amygdala to initiate the behavioral responses needed to deal with the threat.

Yet the brain pathways responsible for picking up threatening information from the body’s sensory system and initiating the fear response are not fully understood, but new research offers some clues.

A recent study from the Salk Institute for Biological Studies in La Jolla, California, may have discovered one such pathway. In the study, scientists discovered populations of a molecule called calcitonin gene-related peptide (CGRP) that allows neurons to transmit threatening signals between separate areas of the brain and then relay that information to the tonsil.

Their research appears in the journal Cell reports.

To conduct the research, the scientists used single-cell calcium imaging to record the activity of CGRP neurons from mice exposed to threat signals that stimulated multiple senses.

Using different colored fluorescent proteins, they were then able to track the pathways of signals leaving the thalamus — a region of the brain responsible for relaying sensory information — and the brainstem. After identifying these pathways, the researchers conducted behavioral tests on mice to assess fear and memory.

When analyzing the data, the scientists found that two distinct groups of CGRP neurons in the brainstem and thalamus transmit signals to the nonoverlapping area of ​​the amygdala, forming two pathways. Moreover, populations of CGRP neurons also translate threatening sensory inputs and communicate them with other brain networks.

Scientists have also found that both pathways are involved in forming unpleasant memories, which can help an individual avoid the same threat in the future.

The study authors suggest that identifying these pathways may offer insights into the treatment of fear-based mental health issues.

Additionally, they hope to examine whether they play a role in multisensory stimulus processing problems, including migraine, autism spectrum disorder (ASD), and post-traumatic stress disorder (PTSD).

According to a press release, co-first author Sukjae Joshua Kang said, “Drugs that block CGRP have been used to treat migraine, so I hope our study can provide a foothold for using this type of medicine to relieve threat memories in PTSD, or sensory hypersensitivity in autism too.

Elizabeth Fedrick, PhD, LPC and owner of Evolve Counseling and Behavioral Health Services in Phoenix, Arizona, said Medical News Today:

“Although some amount of fear and anxiety is normal, overexposure to frightening or stressful events can lead to ‘overactivity’ of fear pathways.” When the fear pathways become overactive, this often results in the development of [..] fear-based mental health disorders.

DTM also spoke with Sung Han, PhD, lead study author and assistant professor at the Salk Institute, about factors that can make these pathways overactive in some people but not others.

“Genetic causes, such as mutation or polymorphism of genes specifically involved in this neural pathway, can inherently alter the signal transmission of this pathway,” Dr. Han said.

“Alternatively, acquired traumatic experiences may also alter the plasticity of this pathway. Both cases can cause hyperactivity or lower the activation threshold of these neurons, thus making them easily activated. These individuals may perceive otherwise normal sensory stimuli as aversive.

– Dr. Sung Han, lead author of the study and assistant professor at the Salk Institute

Previous research has shown that anxious autistic children have larger right amygdala brain volumes than non-autistic children. DTM asked Dr. Han if these results could be correlated to the pathways discovered in the Salk Institute study. He said:

“We don’t know since we haven’t studied the correlative relationship between the enlarged amygdala and the overactivated central alarm pathway that we claim. We can measure the size of the amygdala in mice before and after activation artificial path to test these causalities.

Although future research may test these relationships, Dr. Han said DTM:

“Our immediate plan is to compare the activity of this central alarm system in normal and autistic mouse models to examine whether the autism candidate gene mutation contributes to the hyper excitation of the central alarm network that We have identified.”

Although many mental health conditions can share fear as a driver, “all anxiety disorders stem from an underlying fear,” said Dr. Bruce Bassi, MS, medical director and founder of Telepsych Health in Jacksonville. , in Florida. DTM.

Dr. Bassi notes that fear-based anxiety disorders include:

Treatment options for fear-based mental health disorders include medication, mental health therapy, and mind-body therapies.

Dr Bassi said DTM“drugs targeting anxiety disorders act on key neurotransmitters: serotonin (SSRI), norepinephrine (SNRI), GABA (benzodiazepines) and the adrenergic system (beta-blockers).”

“Therapy, including cognitive-behavioral therapy (CBT), dialectical behavior therapy (DBT), and eye movement desensitization and reprocessing (EMDR), are among the most effective treatment options for treating mental health disorders. based on fear,” said Dr Fedrick. Explain.

“Mind-body strategies attempt to help break the psycho-physiological cycle that can perpetuate anxiety. Biofeedback teaches individuals to learn the physical symptoms associated with anxiety. EMDR and Emotional Freedom Techniques.

– Dr. Bruce Bassi, MS, Medical Director and Founder of Telepsych Health

Yet Dr. Fedrick suggests that when someone with anxiety and fear realizes that a real threat isn’t actually present, it can help activate the parasympathetic system, which is responsible for controlling the ability of the body to relax.

She said DTM that ways to manage anxiety and fear include:

  • Prioritize sleep: Experts suggest that adults should get seven to nine hours of sleep at night for optimal physical capacity and thinking ability.
  • Avoid caffeine: Caffeine causes the release of certain biochemicals that can increase anxiety symptoms.
  • Reduce stress: Identify stressors and use coping strategies including meditation, mindfulness, and deep breathing exercises when feeling stressed.
  • Exercise: Physical activity can release endorphins and other “feel-good” chemicals in the brain. It can also improve sleep.

Dr. Bassi also shared his perspective on managing fear.

“Don’t try to suppress fear or anxiety, but rather embrace it, accept it, dance with it, inspect it, describe it, talk about it, pursue it, befriend it”, said Dr. Bassi. “Do anything with it but try deleting it because it won’t work and it will make you pay more attention to it.”

He also suggests talking about your fears with someone you trust to help normalize them.

“To overcome fear, you have to learn not to be afraid of the sensations of your body. The more your mind focuses on the sensations of your body – your heart racing, you feeling hot and sweaty, shaky, nauseous, the more anxious you will become. […] You can gently remind yourself that you are safe and nothing will happen to you or your heart, and the feeling will pass, as it always does.

— Dr. Bruce Bassi, MS, Medical Director and Founder of Telepsych Health


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