MAPT and Alzheimer disease: In addition, in the final AD stages, NFTs are abundant in the frontal, parietal and occipital neocortex, yet GVBs remain scarce in these areas [13, 132] Although precise quantification of the tau and GVB load is needed to verify these observations, it suggests a model where tau pathology is a prerequisite for GVB formation, but additional factors modulate the process and thereby underly selective vulnerability of specific neuronal populations for GVB development.