Prolonged loneliness can affect transform the brain in a way that makes those who suffer it less able to relate to others, a new study suggests. Research showed that animals kept in isolation for long periods produce less myelin - white matter - in parts of their brain crucial for complex emotional behaviour.
Damaging: A new study shows how prolonged loneliness can actually change the structure of animals' brains, making them less able to relate to peers once their period of isolation is over
The findings from the University at Buffalo and Mt Sinai School of Medicine shed new light on the brain's ability to adapt to environmental changes - a phenomenon known as brain plasticity. Changes in the brain's white matter have been seen before in psychiatric disorders, and demyelinating disorders like multiple sclerosis have also had an association with depression. Recently, myelin changes were also seen in very young animals or adolescents responding to environmental changes.
But Karen Dietz, lead author on the study published online in the journal Nature Neuroscience, said: '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 crucial fatty material that wraps the axons of neurons, helping them signal effectively. Normal nerve function is lost in demyelinating disorders, such as MS and the rare, fatal childhood disease, Krabbe's disease. The paper revealed how the stress of social isolation disrupts the sequence in which the myelin-making cells, the oligodendrocytes, are formed.
Mental health: Changes in the brain's white matter have been seen before in psychiatric disorders, and demyelinating disorders like multiple sclerosis have also had an association with depression
In an experiment, adult mice - normally social animals - were isolated for eight weeks to induce a depressive-like state, before being introduced to a mouse they hadn't met before. While mice are normally highly motivated to be social, those who had been socially isolated did not show any interest in interacting with the new mouse, a typical model of social avoidance and withdrawal.
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Brain tissue analysis of the isolated animals revealed significantly lower than normal levels of gene transcription for oligodendrocyte cells in the prefrontal cortex, a brain region responsible for emotional and cognitive behavior. '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,' said Dr Dietz, a research scientist in the Department of Pharmacology and Toxicology in the UB School of Medicine and Biomedical Sciences.
The key change was that cellular nuclei in the prefrontal cortex contained less heterochromatin, a tightly packed form of DNA material, which is unavailable for gene expression. 'This process of DNA compaction is what signifies that the oligodendrocytes have matured, allowing them to produce normal amounts of myelin,' Dr Dietz said. '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.'
She added, however, that the research also showed that myelin production went back to normal after a period of social integration, suggesting that environmental intervention was sufficient to reverse the negative consequences of adult social isolation. Dr Dietz said the findings have implications for future questions regarding MS and other myelin disorders. 'This research suggests that maybe recovery from an MS episode might be enhanced by social interaction,' she says. 'This opens another avenue of investigation of how mood and myelin disorders may interact with one another.'
Source: Daily Mail UK