For example, SIRT1 has been demonstrated to regulate long-term potentiation and learning and memory.12,13 SIRT1 also promotes cognitive functions in mouse models of Alzheimer disease and Huntington disease.14–16 We have also demonstrated that both SIRT1 and SIRT2 are important to promote oligodendrocyte differentiation from neural stem/progenitor cells.17 Interestingly, both SIRT1 and SIRT2 have also been connected to depressive behaviors.18,19. Here, SIRT1 is linked to Huntington disease.