Here are some fascinating experiments, done in mice to be sure (but likely to be shown for humans soon, as with so many other mouse models). It is known that exposure to an enriched environment enhances learning and memory in mice [which is reflected by an enhancement of nerve-nerve signaling in the hippocampus termed long term potentiation (LTP)]. This new study shows that these effects can be transmitted to the next generation; the authors observed that LTP was enhanced in the offspring of enriched mothers. Moreover, the characteristic defects in LTP and contextual fear conditioning of ras–Gfr-knockout mice were masked in the offspring of knockout mice exposed to an enriched environment. These data raise the intriguing possibility that a mother's experience can induce epigenetic changes that influence her offspring's memory performance (see Tuesday's post for information on another maternal effect and information on epigenetic effects). If a similar phenomenon occurs in humans, the effectiveness of one's memory during adolescence, particularly in those with defective cell signaling mechanisms that control memory, can be influenced by environmental stimulation experienced by one's mother during her youth. A portion of the abstract:
The idea that qualities acquired from experience can be transmitted to future offspring has long been considered incompatible with current understanding of genetics. However, the recent documentation of non-Mendelian transgenerational inheritance makes such a "Lamarckian"-like phenomenon more plausible. Here, we demonstrate that exposure of 15-d-old mice to 2 weeks of an enriched environment (EE), that includes exposure to novel objects, elevated social interactions and voluntary exercise, enhances long-term potentiation (LTP) not only in these enriched mice but also in their future offspring through early adolescence, even if the offspring never experience EE. In both generations, LTP induction is augmented by a newly appearing cAMP/p38 MAP kinase-dependent signaling cascade. Strikingly, defective LTP and contextual fear conditioning memory normally associated with ras-grf knock-out mice are both masked in the offspring of enriched mutant parents. The transgenerational transmission of this effect occurs from the enriched mother to her offspring during embryogenesis.