Brain plasticity is the process in which your brain changes depending on what has happened to it. So it’s the brains ability to rewire itself regardless of age.
Every time you learn a new skill like learning how to drive or learning a new language new pathways in your brain are formed and your cognitive reserve expands. This includes memory, so if you remember this talk tomorrow its because of brain plasticity!
An very interesting study showed that London taxi drivers have a larger hippocampus (in the temporal lobe) than London bus drivers (Maguire, Woollett, and Spiers, 2006). Why is this the case? Taxi drivers have to navigate their way around London and it’s many streets whereas bus drivers follow a limited set of routes. The hippocampus is important for forming and having access to complex memories and in this case spatial memories which are necessary for navigation. So over time the hippocampus of the London taxi drivers got much more stimulation than the London bus drivers.
Brain plasticity an also be observed in the brains of bilinguals. It looks like learning a second language is associated with structural changes in the brain- the left inferior parietal cortex is larger in bilingual brains than in monolingual brains (Mechelli et al., 2004).