HDAC9 and stroke disorder: On the other hand, it may also be possible that the 4–6 days of HDAC inhibition prior to administration of BrdU is insufficient to induce epigenetic changes that underlie SGZ neurogenesis in an immature brain; however, previous studies have shown up-regulation of neurogenesis with 3 day exposure of TSA in adult rats in a stroke model (Kim et al., 2009).