Repeated maternal separation prolongs the critical period of ocular dominance plasticity in mouse visual cortex.

In mammals, maternal separation has been reported to affect brain structure and function in various brain regions; however, its effect on visual system development is largely unknown. In this study, we established a repeated maternal separation (RMS) model in C57BL/6 mice, where the mice pups were separated from their mothers 1 h per day from postnatal day 2 to 8. Ocular dominance plasticity (ODP) was measured at different developmental ages. Interestingly, RMS delayed the opening of critical period (CP) of ODP in female, but not in male mice, while postponed the closure of CP in both sexes. Only female RMS mice maintained the juvenile-like ODP into adulthood. Neither the protein expressions of neither glutamate decarboxylase 65 (GAD65) nor N-methyl-D-aspartate receptor NR2B subunit were altered in visual cortex of RMS mice. No depression/anxiety-like behaviors were detected in RMS mice. These results for the first time reveal that RMS alters the development of ODP.