Introduction
Present collection of atlases of the rat brain in stereotaxic coordinates during the postnatal period has been conceived as a tool for neurscientists using immature rats in their research offering a choice of bregma and lambda as the reference point. Each atlas is a series of 200 micron coronal sections obtained from one rat of a given postnatal age (P, postnatal day, P0 is a day of birth) and present collection includes atlases for P 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 14 and 21 rats. Special care was taken to ensure orientation of the coronal sections vertical to the line between bregma and lambda. This enables targeting of brain structures in stereotaxic coordinates using “artificial skull” for the animal head fixation with positioning lambda and bregma at the same height.