Overo refers to several genetically unrelated pinto coloration patterns of white-over-dark body markings in horses, and is a term used by the American Paint Horse Association to classify a set of pinto patterns that are not Tobiano.
Cerebrospinal fluid signals control the behavior of stem cells in the brain. FULL STORY. When stem cells from the old brain are cultured with signals of a young choroid plexus they can divide and form new neurons (red).
Others regulate the internal environment of the brain, especially the fluid surrounding neurons and their synapses, and nutrify neurons. During early embryogenesis, glial cells direct the migration of neurons and produce molecules that modify the growth of axons and dendrites.