Postweaning social isolation and autism-like phenotype: A biochemical and behavioral comparative analysis.

Researchers studied mice to understand how social isolation during teenage years affects the brain and behavior. They found that mice isolated from other mice during adolescence developed brain changes and reduced social behaviors similar to mice bred to model autism. The isolated mice showed less interest in socializing and made fewer vocalizations, suggesting that social contact during brain development may be important for preventing autism-like behaviors.

This animal study investigated whether social isolation during adolescence produces autism-like behaviors by comparing socially isolated C57BL/6N mice with BTBR mice (an established autism model). Four weeks of post-weaning social isolation led to reduced hippocampal receptors (mGlu2, glucocorticoid, and mineralocorticoid) and decreased social behaviors, mirroring patterns observed in BTBR autism model mice. Both isolated mice and BTBR mice showed reduced social investigation and fewer ultrasonic vocalizations compared to group-housed controls. The findings suggest that lack of social stimulation during critical adolescent brain development can create behavioral and biochemical changes resembling autism spectrum disorder characteristics, supporting the importance of social experiences during this developmental period.

Results highlight the importance of social experiences during adolescent brain development. May inform understanding of environmental risk factors for autism spectrum disorders. Suggests that social isolation interventions should be prioritized during critical developmental periods, though human studies are needed to confirm relevance.

Animal study findings may not directly translate to humans. Sample sizes not reported. Study design details unclear. Limited to male mice only. Short intervention period of four weeks may not capture long-term effects.

Adolescence is a critical period for brain development. In most mammalian species, disturbances experienced during adolescence constitute a risk factor for several neuropsychiatric disorders. In this study, we compared the biochemical and behavioral profile induced by postweaning social isolation (PWSI) in inbred C57BL/6 N mice with that of BTBR mice, a rodent model of autism spectrum disorders. Male C57BL/6 N mice were either housed in groups of four or isolated from weaning (postnatal day 21) for four weeks before experimental analyses.

After weaning, male BTBR mice were housed four per cage and analyzed at 48 days of age. PWSI reduced hippocampal levels of type 2 metabotropic glutamate (mGlu2) receptors, and glucocorticoid and mineralocorticoid receptors. A similar reduction was seen in group-housed BTBR mice. Plasma corticosterone levels in basal conditions were not influenced by PWSI, but were increased in BTBR mice.

Social investigation (total and head sniffing) and the number of ultrasonic vocalizations were reduced in both PWSI mice and age-matched group-housed BTBR mice, indicating a lower social responsiveness in both groups of mice. These results suggest that absence of social stimuli during adolescence induces an endophenotype with social deficit features, which mimics the phenotype of a mouse model of autism spectrum disorders.