The COVID-19 outbreak has forced several countries to implement social distancing and school shutdown. Though our world is increasingly connected over digital platforms still young people are feeling an increasing sense of isolation. Isolation can cause brain damage to children. It is recognized as a serious threat to children’s mental health. So we are required to understand the mental health consequences of isolation and social distancing.

Brain Circuit Could Be Damaged by Social Isolation during Childhood

While studies have shown that social isolation during childhood is harmful to adult brain function and behavior across mammalian species, the underlying neural circuit mechanisms have remained poorly understood. Researchers experimented with male mice to observe the effects of social isolation.

The study was conducted by the Icahn School of Medicine research team at Mount Sinai has found that specific subpopulations of brain cells in the prefrontal cortex, a vital part of the brain that regulates social behavior, that are essential for normal sociability in adulthood and are extremely vulnerable to juvenile social isolation in mice.

The research findings appeared in the August 31 issue of Nature Neuroscience, clarified previously unrecognized function of these cells, called medial prefrontal cortex neurons projecting to the paraventricular thalamus, the brain part that transfers signals to different components of the brain’s reward circuitry. If the study is reflected in humans, it could direct to medications or therapies for psychiatric disorders associated with isolation.

Hirofumi Morishita, MD, PhD, Associate Professor of Psychiatry, Neuroscience, and Ophthalmology at the Icahn School of Medicine at Mount Sinai, a faculty member of The Friedman Brain Institute and the Mindich Child Health and Development Institute, and senior author of the paper stated, “In addition to identifying this specific circuit in the prefrontal cortex that is particularly vulnerable to social isolation during childhood, we also demonstrated that the vulnerable circuit we identified is a promising target for treatments of social behavior deficits,” furthers added, “Through stimulation of the specific prefrontal circuit projecting to the thalamic area in adulthood, we were able to rescue the sociability deficits caused by juvenile social isolation.”

Particularly, the team discovered that, in male mice, after two weeks of social isolation immediately following weaning led to a failure to activate medial prefrontal cortex neurons projecting to the paraventricular thalamus throughout social exposure in adulthood. Researchers discovered that juvenile isolation led to both increased inhibitory input from other related neurons and reduced excitability of the prefrontal neurons projecting to the paraventricular thalamus.

The researchers utilized chemogenetics in their study. While optogenetics allows researchers to stimulate specific neurons in freely walking animals with pulses of light, chemogenetics permits non-invasive chemical control over cell populations. By using both of these techniques, the researchers were able to swiftly improve social communication in these mice once light pulses or drugs were given to them.

 Dr. Morishita said, “We checked the presence of social behavior deficits just prior to stimulation and when we checked the behavior while the stimulation was ongoing, we found that the social behavior deficits were reversed.”

 Due to social behavior deficiencies, it can lead to various psychiatric disorders and neurodevelopmental disorders, which include autism and schizophrenia. The circuits detected in this study could possibly be modulated using techniques like transcranial direct current stimulation and transcranial magnetic stimulation.