One study indicated the upregulation of histone deacetylase HDAC1 in the hippocampi of patients. Aragonite scaffolds have recently been shown to support the growth of neurons from rat hippocampi. This acetylation contributes to upregulation of "Bdnf" in the brain hippocampi of rats. However, the hippocampi of these mice show disorganisation in the CA3 region. Humans and other mammals have two hippocampi, one in each side of the brain. These include bulls, birds, hippocampi, a panther, a lion and a goat.