This report investigates a new possible molecular mechanism for the pathogenesis of hydrocephalus. New research by Dr. Miles Johnston has found that the injection of anti beta_1 integrin antibodies into the ventricle of rats causes a drop in parenchymal pressure and causes the cerebral ventricles to enlarge which is characteristic of hydrocephalus. We investigate intramantle pressure gradients as a possible force to enlarge the ventricles and we propose a new poroelastic model incorporating the effect of the antibodies to determine if they are a possible mechanism for hydrocephalus