Washington D.C. [USA], Feb 21 : While studying an animal model, researchers have found that social isolation during key developmental windows drives long-term changes in activity patterns of neurons involved in initiating social approach.
Mount Sinai Researchers Corresponding Author Hirofumi Morishita, MD PhD, together with Schahram Akbarian, MD, PhD, Icahn School of Medicine at Mount Sinai, New York, and other co-authors (first author Lucy Bicks) conducted the study. It was published in the journal Nature Communications.
Bottom Line: Loneliness is increasingly being recognised as a serious threat to mental health and well-being in our society. Our study in an animal model shows that social isolation during adolescence leads to long-term disruptions in social behaviour and disruptions to activity patterns of a type of inhibitory neuron in the brain, which are frequently disrupted in psychiatric disorders including Schizophrenia. Activity patterns of these inhibitory neurons are sufficient to rescue social deficits induced by juvenile social isolation.
Results: Social behaviour is composed of interactions where mice are actively exploring conspecifics or passively being explored. We find one population of neurons, parvalbumin-expressing inhibitory neurons, increases in activity prior to an active, but not a passive social interaction. The brief activity of these neurons is sufficient to promote increased active social behaviour. Juvenile social isolation during adolescence disrupts the activity of these neurons, leading to a decoupling of their activity and subsequent active social behaviour initiation. Increasing activity of these neurons in adult animals that were socially isolated during adolescence restores normal social behaviour.
Why the research is interesting: The findings help us to understand how social experience during key windows of development might shape long term behavioural outcomes through changes to specific circuits in the brain. Understanding how social experience shapes outcomes can help us to overcome social deficits in cases of early life trauma or in neurodevelopmental and psychiatric disorders with social deficits.
Who: Mouse models deprived of social experience during the juvenile period.
When: Mice were deprived of social experience during a juvenile phase and their behaviour and physiology were examined in adulthood.
What: The study measured the activity of parvalbumin-expressing inhibitory neurons during social interaction as well as input drive to these neurons.
How: We measured parvalbumin-expressing inhibitory neuron activity during social behaviour and manipulated the activity of these neurons using advanced technologies.
Study conclusions: Social experience early in life alters specific patterns of parvalbumin-expressing inhibitory neurons in the prefrontal cortex. This pattern of activity is essential for active social approach behaviour in mice.