Ependymal cilia: distribution and activity in the adult human brain.

Examination of 150 to 200 samples of the ependymal lining of the ventricles of nine adult human brains obtained 2(1/2) to 6 hours post-mortem revealed cilia in at least 20 separate sites in the four ventricular cavities. In seven of the brains ciliary motion was evident, and in two of these it was wide-spread and rapid. It seems likely that the adult human ventricular ependyma is ciliated throughout. Currents having distinct patterns are induced in the ventricles of animal brains by ciliary motion, and such currents probably exist in man. A local mechanism for the rapid movement of cerebrospinal fluid is therefore present.