Fig. 2. Hypothetical diagram of autoregulation of the cerebral vasculature based on Chillon and Baumbach (21). Cerebral arterial diameter (- - -) and cerebral blood flow (—) are plotted against arterial pressure. Cerebral resistance arteries are shown as dilating during reduction and constricting during increases in mean arterial pressure. This serves to maintain relatively constant cerebral blood in the range of pressures diagrammed as the autoregulatory plateau. Beyond the range of the autoregulatory plateau, vessel diameter is shown as responding passively to changes in arterial blood pressure.