In recent investigations, the angular dependence of the BOLD signal with respect to the main magnetic field has been shown by Monte Carlo simulations and experimental approaches. This orientation dependence is often attributed to the contribution of large vessels (cortical surface and penetrating arteries/veins). However, the ability to resolve cortical layers and columns depends ultimately on the contribution of the MR signal generated by the capillary bed. In this work, we studied the MR signal attenuation generated by a vascular network model that was acquired from the parietal cortex of mice using a two-photon laser imaging techniques. We separately investigated the impact of macrovessels (>5 µm in diameter) and microvessels (< 5 µm in diameter) on the BOLD effect.