Dynamic coupling of blood flow to function and metabolism in the optic nerve head

Abstract

Increased neuronal activity induced by diffuse flickering illumination of the ocular fundus generates increases in blood flow and decreases in tissue pO 2 in the optic nerve head (ONH). This suggests that in the ONH, as in the brain, a coupling exists between function, perfusion, and metabolism, in accordance with the hypothesis of Roy and Sherrington. Following a review of the characteristics of the activity-induced blood flow response in the cat ONH, the relationship between blood flow and metabolism is discussed. We then examine possible mediators of the neurovascular coupling, some of the factors which may interfere with it, and point out various problems which remain to be addressed in order to better understand this coupling.