Reduced number of brain cells in so-called neural overgrowth.

Patten described as neural overgrowth a folding of brain tissue into the ventricles in abnormal human embryos. Intubation of chick embryo brains release cerebrospinal fluid pressure resulting in a similar folding. These folded brains have 2.5 times less tissue volume than control embryos of identical stage. This study shows, with total DNA measurements, that brain cell number is 50% less in folded brains (intubated embryos) as compared to control brain of identical staged embryos.