Alzheimer's disease-related lesions.

The invitation to contribute to "Alzheimer's Disease: Advances for a New Century" gave me an opportunity to briefly summarize my personal opinions about how the field of neuropathology has evolved. The goal is to briefly exemplify the changes that have influenced the way we conduct our diagnostic work as well as the way we interpret our results. From an era of histological stains, we have moved to visualization of altered proteins in predicted brain regions; we have also realized that in many aged subjects, not one but a plethora of co-pathologies are seen, and finally, we have become aware that the degenerative process is initiated much earlier than we ever suspected.