An insulating layer that forms around nerves, including those in the brain and spinal cord. It is made up of protein and fatty substances. The purpose of the myelin sheath is to allow impulses to transmit quickly and efficiently along the nerve cells. If myelin is damaged, the impulses slow down. This can cause diseases such as multiple sclerosis.
"The weakness or even complete absence of a social support network in a person's life forms the basis for identifying someone who is socially isolated. "
Research performed recently has discovered that social isolation disrupts the process of, "myelination," of a person's brain cell axons by, "oligodendrocytes." Researchers discovered that animals that are socially isolated over extended periods of time produce less myelin in the area of their brains that is responsible for complex cognitive and emotional behaviors. The research was performed by professionals at the University at Buffalo and Mt. Sinai School of Medicine.
The research presents a new perspective related to brain plasticity, the ability of a person's brain to adapt to environmental changes. It shows that neurons are not the only brain structures that experience changes in response to a person's experiences and the environment they are in according to Karen Dietz, Ph.D., a research scientist in the Department of Pharmacology and Toxicology in the University of Buffalo School of Medicine and Biomedical Sciences. Dr. Dietz conducted her work as a post-doctoral researcher at Mt. Sinai School of Medicine. Jai Liu, Ph.D. is another Mt. Sinai post-doctoral researcher involved in the research, as is Patrizia Casaccia, M.D., Ph.D. Professor of Genetics and Genomic Sciences, Neuroscience and Neurology.
The research noted that changes in the white matter of a person's brain or, 'myelin,' has never been seen before in psychiatric disorders and demyelinating disorders have also been associated with depression. Changes in a person's myelin have also been recently observed in very young animals or teenagers responding to changes in their environment through the research performed. Doctor Dietz stated, "This research reveals for the first time a role for myelin in adult psychiatric disorders. It demonstrates that plasticity in the brain is not restricted to neurons, but actively occurs in glial cells, such as the oligodendrocytes, which produce myelin."
Myelin is a critical fatty material that wraps the axons of a person's neurons, allowing them to signal effectively. Effective nerve functioning is lost in demyelinating disorders such as Multiple Sclerosis and Krabbe's disease, a rare and fatal form of childhood disease. The results of the research reveal that stress related to social isolation disrupts the sequence in which a person's myelin producing cells, the oligodendrocytes, are formed.
In the experiment during the research process adult mice, usually social animals, were isolated over a period of eight weeks to induce a depressive-like state. The animals were then introduced to a, 'novel,' mouse - one they had not encountered before. While mice are usually highly motivated socially, the ones that had been socially isolated did not demonstrate any interest in interacting with the new mouse that had been introduced to their environment, a model of withdrawal and social avoidance.
An analysis of the brain tissue of the animals that were socially isolated showed significantly lower than usual levels of gene transcription for oligodendrocyte cells in their prefrontal cortexes, the region of their brains responsible for cognitive and emotional behaviors. Dr. Dietz stated, "This research provides the first explanation of the mechanism behind how this brain plasticity occurs. Showing how this change in the level of social interaction of the adult animal resulted in changes in oligodendrocytes."
The crucial change was that cellular nuclei in the prefrontal cortex contained less heterochromatin. Heterochromatin is a tightly-packed form of DNA material that is unavailable for gene expression. Dr. Dietz said, "This process of DNA compaction is what signifies that the oligodendrocytes have matured, allowing them to produce normal amounts of myelin. We have observed in socially isolated animals that there isn't as much compaction, and the oligodendrocytes look more immature. As adults age, normally, you would see more compaction, but when social isolation interferes, there's less compaction and therefore, less myelin being made."
Dr. Dietz also noted that the research demonstrated myelin production returned to usual levels, however, after a period of social reintegration. What this suggests is that environmental intervention was sufficient enough to reverse the negative consequences of adult social isolation. The observation is important because it means the process of demyelinization is reversible.
The research, in conjunction with a report published earlier this year by another group, show that myelin changes triggered by social isolation early in a person's life will widen future investigations into brain plasticity according to Doctor David Dietz, Assistant Professor of Pharmacology and Toxicology at the University of Buffalo. Doctor Karen Dietz states the work performed has incredible implications for future work related to Multiple Sclerosis and other myelin disorders. She stated, "This research suggests that maybe recovery from an MS episode might be enhanced by social interaction. This opens another avenue of investigation of how mood and myelin disorders may interact with one another."
'Social isolation,' might be defined structurally as the absence of social contacts, interactions, as well as relationships with family members, friends, and neighbors on an individual level and with people in society at large on a wider level. A meager definition of social support might be, 'resources provided by others.' The resources may include social, emotional, financial, physical, or other types of care and cover an array of people and institutions. Social isolation may also be defined and measured by the strength of a person's existing social network and the characteristics of the people and institutions providing them with support in their network.
The weakness or even complete absence of a social support network in a person's life forms the basis for identifying someone who is socially isolated. The definition is a qualitative one indicating the absence of relationships that are meaningful to the person. Social support has been and continues to be used as an indicator of the degree of a person's social isolation. It can also serve as the largest independent variable in studies of the effect of social isolation as a risk factor of dysfunction or disease. The level of social support someone receives may serve as an outcome variable of the quality of a person's life.
Few studies exist in regards to the prevalence of social isolation. The ones that do exist indicate a complete absence of relationships is fairly rare among seniors as a population. In addition, when social isolation is identified as a condition among seniors, it is usually accepted as the continuation of a lifelong pattern instead of a late in life development. Seniors may perceive themselves to be dependent or frail and might isolate themselves with the intention of disguising a perceived loss of autonomy. The limited amount of evidence available on the prevalence of social isolation appears to confirm a low prevalence of true social isolation.
Despite a lack of evidence concerning total isolation among seniors, work has been completed suggesting the existence of fairly low levels of social support for the population. Follow-up study of research involving a population of seniors found thirty-five percent of the participants surveyed reporting a lack of a confidant, or someone who by definition was a person the participant felt they could talk about serious issues with, who was readily available to them, and with whom they had contact with on at least a monthly basis.
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