¹¹Increase in plasticity due to food restriction: (Spolidoro et al., 2011); environmental enrichment: (Sale et al., 2007); exercise and games: (Bavelier et al., 2010; Nokia et al., 2016). See also Kirste et al. (2015) who show how both silence and unusual noise can increase neurogenesis in the hippocampus (and thus plasticity), which they assume is due to the novelty of both conditions.