[Neurohistologic and morphometric examinations of the ontogenesis of the regio cingularis mesoneocorticalis in the rat].

The neuronal structure of the Regio cingularis mesoneocorticalis has been studied by means of GOLGI-impregnated brains of embryonic and neonatal rats. The morphometrical analysis has been carried out at 36 pyramidal neurons from layer V and 18 interneurons of the different ages of animals. We have found two staps of development: continuous growth and rapid development. The most frequent staps of rapid development between the stages P 0 and P 5 and between P 10 and P 15 indicate the influence of extrinsic factors. The connection of the neuron-growth in the late ontogenesis and the embryonic processes of proliferation, migration and lamination is discussed.