PTSD and Anxiety Behaviors Linked to Myelin Increase in the Brain's Gray Matter

A recent study conducted by researchers from the University of California Berkeley links anxiety and PTSD behavior in rats to an increase in myelin- a substance in the brain's gray matter that expedites the communication mechanisms between neurons- in areas of the brain that are associated with memory and emotions.

The study results give a probable explanation as to why some people are resilient while others are vulnerable to traumatic stresses, and for the varied symptoms such as anxiety, avoidance behavior, fear, and more are triggered by the memory of said stresses. Suppose the findings of the researchers are correct. In that case, extreme trauma causes a sudden increase in myelination that could lead to future treatments and drug intervention to prevent, or even more, reverse the myelin production and lessen the effects of extreme trauma.

Understanding Myelins Role

(Photo: Huy Phan from Pexel)

Myelin, according to MedlinePlus, is an insulating layer, like a sheath, of fatty substances and proteins which form around the nerves. Essentially it acts as insulation for the brain's inner wirings to facilitate long-distance signal transmissions and communication between different distant areas of the brain. In fact, the inner regions of the brain are also referred to as white matter due to myelin encasing the large bundles of axons.

However in the recent study published in the journal Translational Psychiatry, titled "Regional gray matter oligodendrocyte- and myelin-related measures are associated with differential susceptibility to stress-induced behavior in rats and humans," found evidence suggesting that increases in myelination of the axons, also known as gray matter, where most of the cell bodies reside and most of the wiring is less insulated in the protein. The extra myelination was primarily found in the brain regions linked with memory.

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Discovering the Relationship of Anxiety and PTSD Symptoms with the Brain's Gray Matter

38 veterans were scanned with MRI by researchers from the San Francisco Veterans Affairs Medical Center, half of whom had PTSD while the other half did not. They found that an increase in myelination in the brain's gray matter occurred in those with PTSD compared to the levels of myelin in the control group that did not suffer from PTSD, reports NeuroScience.

Both veterans diagnosed with PTSD and stressed rats that exhibited avoidance behavior had increased myelination in the hippocampus, often believed to be the seat of memory. Those who showed a fear response, on the other hand, had increased myelination in the amygdala that plays a vital role in a person's response to strong emotions like pleasure or fear. Likewise, participants suffering from anxiety had increased myelination in the dentate gyrus, a region in the brain critical to memory and learning.

Dr. Thomay Neylan, the senior author of the study and the director of the Posttraumatic Stress Disorders Clinic at the San Francisco VA, says that the combination of the studies in veterans and rats with PTSD gives another mechanism that should be used to be considered as new treatments are developed.