Oligodendrocytes in the periaqueductal gray matter and the corpus callosum in adult male and female domestic sheep

•The knowledge about oligodendrocytes (OLGs) in the Periaqueductal Gray matter (PAG) has not been described enough yet.•OLGs are not only confined to myelination in young individuals, but also play a crucial role in the brain of adults.•Glial cells in OLG-myelin fibres, correlation in adults regardless of sex even after the creation of the completion of myelin.