Raising mice in an enriched environment (better opportunities for social interaction, voluntary physical exercise & explorative behaviour) boosts cortical plasticity & now ocular dominance plasticity

Transgenerational transmission of enhanced ocular dominance plasticity from enriched mice to their non-enriched offspring. Evgenia Kalogeraki, Rashad Yusifov and Siegrid Löwel. eNeuro January 21 2019, ENEURO.0252-18.2018; https://doi.org/10.1523/ENEURO.0252-18.2018

Abstract: In recent years, evidence has accumulated that non-Mendelian transgenerational inheritance of qualities acquired through experience is possible. In particular, it has been shown that raising rodents in a so-called enriched environment (EE) can not only modify the animals’ behaviour and increase their susceptibility to activity-dependent neuronal network changes, but also influences both behaviour and neuronal plasticity of the non-enriched offspring. Here, we tested whether such a transgenerational transmission can also be observed in the primary visual cortex (V1) using ocular dominance (OD) plasticity after monocular deprivation (MD) as a paradigm. While OD-plasticity after 7 days of MD is absent in standard-cage (SC) raised mice beyond postnatal day (P) 110, it is present lifelong in EE-raised mice. Using intrinsic signal optical imaging to visualize cortical activity, we confirm these previous observations and additionally show that OD-plasticity is not only preserved in adult EE-mice but also in their adult non-enriched offspring: mice born to enriched parents, but raised in SCs at least until P110 displayed similar OD-shifts towards the open eye after 7 days of MD as age-matched EE-raised animals. Furthermore, testing the offspring of EE-female versus EE-males with SC-mating partners revealed that only pups of EE-females, but not of EE-males, preserved OD-plasticity into adulthood, suggesting that the life experiences of the mother have a greater impact on the continued V1-plasticity of the offspring. The OD-plasticity of the non-enriched pups of EE-mothers was, however, mechanistically different from that of non-enriched pups of EE-parents or EE-mice.

Significance statement:  Recently evidence is accumulating that life experiences and thus acquired qualities of parents can be transmitted across generations in a non-Mendelian fashion and have a significant impact on the fitness of offspring. Raising mice in a so-called enriched environment with enhanced opportunities for social interaction, voluntary physical exercise and explorative behaviour has been shown to boost cortical plasticity. Our results now show that the plasticity-promoting effect of enrichment on ocular dominance plasticity, a well-established plasticity paradigm in a primary sensory cortex, can also be transmitted from enriched parents to their non-enriched offspring. Thus cortical plasticity is not only influenced by an animal’s life experiences but can also be modified by the life experiences of its parents.