A MATHEMATICAL-MODEL OF THE INTRACRANIAL SYSTEM INCLUDING AUTOREGULATION

Cerebral autoregulation plays an important role in the dynamic process es of intracranial physiology. This work develops a four-compartment, lumped-parameter model for the interactions of intracranial pressures, volumes, and flows as a test bed for examining the consistent inclusi on of explicit autoregulation in mathematical models of the intracrani al system. It is hypothesized that autoregulation of the blood supply from the arterioles to the capillary bed can be modeled by allowing th e flow resistance at the interface of the artery and capillary compart ments in the model to be a function of pressure rather than a constant The functional dependence on pressure of this resistance parameter is not specified in advance, but emerges naturally from the assumed rela tionship between pressure differences and flows. Results show that a c onstant flow from the artery to the capillary compartment can be maint ained by a flow resistance which is directly proportional to the press ure difference between these two compartments. Oscillatory flow is ree stablished in the model at the capillary-cerebrospinal fluid and capil lary-venous interfaces.