Rat Brain Cortex Neurons from rat (E18, 19) brain are cell suspensions of high quality primary embryonic brain neuronal cells (including glia) prepared by standardized methods, and are ready for immediate culture. Each vial of cortical cells contains approximately 4 million viable cells. This will seed into 10 or more wells of a 24-well plate and 50 or more wells of a 96-well plate using the recommended plating densities and medium. Cell death will occur during the first few days after plating and debris will be observed. This is normal. After approximately 4 days in culture, the cells will form a neurite network and by the 7th day, debris will be minimal.