Fig. 1. Dendritic arbor development of layer 5 pyramidal neurons in the medial prefrontal cortex of Wistar rats during the first month of postnatal life. (A ) Representative Neurolucida reconstructions of Lucifer Yellow-injected pyramidal neurons in layer 5 of the medial prefrontal cortex at postnatal days 5, 10, and 30 showing the temporal evolution of dendritic arborization pattern in these cells during the first postnatal month. (B ) Quantitative analysis describing the temporal evolution of apical (red columns ) and basal (blue columns ) dendritic lengths and (C ) branching points during this same period. Results are expressed as mean ± SD. *=P < 0.05; **=P <0.01; ***=P < 0.001, one-way ANOVA with Bonferroni correction posttests performed between subsequent age groups in either basal or apical tree, n = 4 animals for age groups PND 5, 10, 20 and n = 5 animals for age group PND 15. (8–12 injected cells were averaged for each animal). PND= postnatal day; scale bar = 100 μm.