Much experimental evidence suggests that age-related brain pathologies are most often mediated by reactive oxygen species primarily originating from mitochondria (mROS). Two papers with such evidence have been recently published in the Journal of Alzheimer's Disease (Stefanova et al., J Alzheimers Dis 21, 476-491, 2010; Lloret et al., J Alzheimers Dis, doi: 10.3233/JAD-2011-110890). In the firs...