Neural stem cells give rise to new neurons in the adult mammalian brain. Forebrain ependymal cells lining the lateral ventricles have been proposed as a candidate neural stem cell, although some studies suggest that they are quiescent and terminally differentiated.
A remarkably well-preserved brain has been discovered in a 300-million-year-old fossil of a fish from Kansas. Philippe Janvier of the National Museum of Natural History in Paris and his colleagues used X-rays from the European Synchrotron Radiation Facility in Grenoble, France, to peer inside the skulls of iniopterygians, extinct relations of modern sharks and ratfish.
Finding gene regulators in the fruitfly Drosophila melanogaster has proved difficult: looking for conserved non-coding DNA sequences, a method that works well in vertebrates, has been unsuccessful. Michael Eisen at the University of California, Berkeley, and his co-workers suggest that this is because the fly's genome is compact — not because its regulatory architecture differs substantially from that of vertebrates.
Neural stem cells give rise to new neurons in the adult mammalian brain. Forebrain ependymal cells lining the lateral ventricles have been proposed as a candidate neural stem cell, although some studies suggest that they are quiescent and terminally differentiated. 
