Chennai: A team of researchers from the Icahn School of Medicine at Mount Sinai has identified specific sub-populations of brain cells in the prefrontal cortex, a key part of the brain that regulates social behavior, that are required for normal sociability in adulthood and are profoundly vulnerable to juvenile social isolation in mice.
Published in Nature Neuroscience, findings of the study shed light on a previously unrecognised role of these cells, known as medial prefrontal cortex neurons projecting to the paraventricular thalamus, the brain area that relays signals to various components of the brain’s reward circuitry. If the finding is replicated in humans, it could lead to treatments for psychiatric disorders connected to isolation.
According to Hirofumi Morishita, 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, “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.”
“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.”
Specifically, the team found that, in male mice, two weeks of social isolation immediately following weaning leads to a failure to activate medial prefrontal cortex neurons projecting to the paraventricular thalamus during social exposure in adulthood.
Researchers found that juvenile isolation led to both reduced excitability of the prefrontal neurons projecting to the paraventricular thalamus and increased inhibitory input from other related neurons, suggesting a circuit mechanism underlying sociability deficits caused by juvenile social isolation.
Dr Morishita added: “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.”
Given that social behavior deficits are a common dimension of many neurodevelopmental and psychiatric disorders, such as autism and schizophrenia, identification of these specific prefrontal neurons will point toward therapeutic targets for the improvement of social behavior deficits shared across a range of psychiatric disorders.