Primary cilia in normal human neocortical neurons.

Human neocortical neurons from the frontotemporal region were examined by serial ultrathin sectioning with the intention to establish the morphology and frequency of primary cilia (with a 9 + 0 tubular structure) in these cells. Each cell examined thoroughly showed one single cilium with a characteristic position and structure. The constant presence of these organelles may be a hint at an important function.