Loneliness is recognized as a serious threat to mental health. Even as our world grows on digital platforms, the youth of our society are increasing the feeling of isolation. The COVID-19 epidemic, which forced many countries to implement social distinctions and school closures, increases the need to understand the mental health consequences of social isolation and loneliness. While research has shown that social isolation during childhood is particularly detrimental to adult brain function and behavior in mammalian species, the underlying neural circuit mechanisms remain poorly understood.
A research team at the Icon School of Medicine in Mount Sinai has now identified specific sub-populations of brain cells in the prefrontal cortex, a major part of the brain that regulates social behavior, which is common in adulthood. Are required for and are profoundly vulnerable adolescents to social isolation in mice. The study’s findings, which appear in the August 31 issue Nature neuroscienceShed light on the previously identified role of these cells, known as medial prefrontal cortex neurons for the paraventricular thalamus, the brain region that signals various components of the brain’s reward circuitry. If this finding is repeated in humans, it can lead to treatment for psychiatric disorders associated with isolation.
“In addition to identifying this specific circuit in the prefrontal cortex, which is particularly vulnerable to social isolation in childhood, we also demonstrated that the sensitive circuits we have identified for the treatment of social behavior deficits Is a promising goal, “says Hirofor Morishita, MD, Ph. D. Member and senior author of the paper. “Through stimulation of specific prefrontal circuits presenting the thalamic region in adulthood, we were able to defend against the lack of sociality caused by adolescent social isolation.”
In particular, the team found that, in male mice, weaning immediately after two weeks of social isolation is followed by failure to activate medial cortex neurons that are associated with the paraventricular thalamus during social exposure in adulthood. Researchers found that juvenile isolation reduced stimulation of prefrontal neurons related to the paraventricular thalamus and increased inhibitory input from other related neurons, suggesting a circuitous mechanism of sociality underlying adolescent social isolation. To determine whether rapid restoration of activity of the prefrontal projection to the paraventricular thalamus is sufficient for a substantial amount of sociodemographic reduction in adult mice that undergo juvenile social isolation, the team employed a technique known as optogenetics That stimulated prefrontal projection to the paventricular thalamus. Researchers also used chemistry in their studies. While optogenetics enables researchers to stimulate specialized neurons in freely moving animals with pulses of light, chemogenetics allows non-invasive chemical control over cell populations. By employing both of these techniques, researchers were able to rapidly increase social interaction in these mice when administering mild pulses or drugs.
Dr. Morishita said, “We checked for the presence of a lack of social behavior just before the stimulus and when we checked the behavior, we found that the lack of social behavior was reversed.”
Given that the lack of social behavior is a common dimension of many neurodevelopmental and psychiatric disorders, such as autism and schizophrenia, identifying these specific prefrontal neurons would point to therapeutic goals for the improvement of shared social behavior across a range of psychiatric disorders. . The circuits identified in this study could possibly be modified using techniques such as transcranial magnetic stimulation and / or transcranial direct current stimulation.
Social isolation affects brain development in mice
A prefrontal – paraventricular thalamus circuit requires juvenile social experience to regulate adult sociality in mice, Nature neuroscience (2020). DOI: 10.1038 / s41593-020-0695-6, www.nature.com/articles/s41593-020-0695-6
Provided by Mount Sinai Hospital
Quotes: Researchers discovered a specific brain circuit damaged by social isolation during childhood (2020, 31 August). Retrieved 1 September 2020 from https://medicalxpress.com/news/2020-08-specific-brain-circuit-social-isationation.html.
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