Neuropathological brain mapping is enabled by extensive semiserial sectioning with whole brain coronal microscopical sections prepared from every 5 to 15 mm. By this method not only type of change but also distribution and regional severity can be assessed, which is fundamental for a correct neuropathological diagnosis. This has proved to be of vital importance for the correlation and validation of the clinical symptoms and brain imaging findings in cases of organic dementia, and vice versa for the interpretation of the neuropathological findings. Different patterns for the distribution and types of changes have been revealed for Alzheimer's disease and frontal lobe degeneration, as well as in vascular dementia where pure subgroups could be identified. In the very aged, the mapping of several types of mild lesions have been shown to cooperate to cause a summational dementia.