In order to better understand the mechanisms of cerebrovascular development and differentiation, the leptomeningeal microcirculation was analyzed using in vivo fluorescence video-microscopy in neonatal (1, 9, and 12 day old) Sprague-Dawley rats. The pattern of flow distribution was reconstructed, the location of radially emerging intracortical veins was identified and the minimum distance between these vessels was measured. We found no AV connections in the leptomeningeal vasculature of the neonatal rat in all examined animals. The LVP in the neonatal period of life is a venous system and probably does not serve as a major source of oxygen supply to cerebral tissue. After birth, the number of radial vessels does not increase, suggesting that intracortical vascularization continues by the branching of existing radial vessels.