Blood flow disturbances within the brain microvasculature may cause microinfarcts, which are associated with the development of neurodegenerative diseases. Understanding oxygen dynamics in the brain tissue surrounding the microvasculature is essential to assess the vascular network’s robustness to microinfarcts. This work investigates whether local blood flow direction influences the contribution of individual vessels to cerebral oxygen supply. An in silico approach is adopted, since direct measurements of oxygen concentration are limited. Computational models of blood flow and oxygen dynamics are developed and applied. Simulations are performed on a realistic microvascular network extracted from a mouse somatosensory cortex. The variable vessel topology is introduced, classifying vessels into four groups, called topological configurations, based on local blood flow direction.