Everyone handles fear differently. Have you ever wondered why some people are fearless, while others are afraid of their own shadows? Fear is a natural human emotion that arises when we feel threatened or harmed. Fear can be rational or irrational. In some cases, like post-traumatic stress disorder (PTSD) or anxiety-related disorders, fear responses can be uncontrolled or exaggerated. Researchers have been trying to figure out what specifically triggers fear and how it turns into a long-term memory. 

Depression - a lonely alcoholic in fear covers his face with his hands

This study from researchers at Linköping University investigated the biological mechanisms that impact fear-related memories in the brain. They used rats and discovered potentially groundbreaking data behind anxiety-related disorders and alcohol dependence. For those of us who need a quick lesson on the brain, the amygdala regulates emotions and is activated by endangerment or threats. The nerve cells connect the frontal lobe to the amygdala. Interestingly, the research found that these connections are changed in people with anxiety-related disorders. 


Specifically, they investigated a protein known as PRDM2. This protein encodes a zinc finger protein that can bind to different types of proteins and receptors. Levels of PRDM2 seem to play an important role in exaggerated stress responses and are also lower in those who are alcohol-dependent. It is common for anxiety-related disorders and alcohol dependency to be present at the same time, and the researchers suspect that this is caused by the protein. 


A little more review on the science of the brain is needed before we continue.  The formation of memories are complex and may be connected to our fear responses.  Consolidation is when new memories are formed and preserved into long-term memories. Increased activity between the frontal lobes and amygdala increases learned fear reactions. The decrease in PRDM2 increases the consolidation of fear-related memories. 

Mental Health - The Noun Project

The research suggests that patients with anxiety-related disorders may benefit from treatments that weaken fear memories. Researchers have discovered a way to down-regulate PRDM2, but do not have a way of increasing it, yet. This mechanism could be a part of the explanation as to why individuals have a greater susceptibility to anxiety-related disorders and why these disorders are commonly associated with alcohol dependency. 

Protein PRDM2 PDB 2JV0

One thing we have learned thus far in AP Biology class is that ribosomes are protein factories located free in the cytosol or bound to the rough endoplasmic reticulum or nuclear envelope. Within the rough endoplasmic reticulum, proteins are produced to either be secreted outside the cell, membrane-embedded proteins, or proteins to go inside organelles. 


Although they have not discovered a way to increase PRDM2, it is very interesting for us to be able to understand how our fear memories turn into long-term memories and what causes individuals to be more vulnerable to mental health disorders. Hopefully, with the continued research on the biological mechanism that may cause fear, we can reverse engineer the cause and create new innovative medicines to treat and, perhaps, completely cure them. 

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