Selective growth of hippocampal neurites on cryostat sections of rat brain

Dissociated rat hippocampal neurons were cultured on horizontal cryostat sections from neonatal and adult rat brain and their growth patterns visualized by brightfield and interference contrast microscopy. Cells adhered to the sections as individuals or in small clusters and grew extensive neurites. Neurites grew over all areas of neonatal sections without apparent selectivity. For adult sections, however, neurites grew almost exclusively on areas of grey matter: there was no neurite growth on areas of white matter, irrespective of the location of that white matter within the brain. The transition from the neonatal to the adult pattern of growth occurred for sections from animals aged between 14 and 21 days.