Not only brain plasticity. Biologically, I think many systems in our body stop being flexible. For example, there's a recent discovery which shows with age we

Not only brain plasticity. Biologically, I think many systems in our body stop being flexible. For example, there's a recent discovery which shows with age we loose a particular population of naive T cells that binds to a really wide class of antigens [1]. If we were able to restore that population, I imagine it could potentially have big implications in how we age, as our immune system would keep learning forever. SENS tries to answer lots of these questions too. I think brain plasticity or immune plasticity can be restored. It will just take time to unravel all the epigenetics, but some principles are already popping up. [1] http://biorxiv.org/content/early/2016/06/17/059535 http://biorxiv.org/content/early/2016/06/17/059535