Rare study reveals a striking divide inside an Alzheimer’s patient’s brain
A rare examination of an Alzheimer’s patient’s brain revealed that regions cleared of amyloid plaques had remarkably little of the harmful tau buildup associated with memory loss, while neighboring areas showed extensive damage. The discovery suggests that removing amyloid may have lasting protective effects and could help slow Alzheimer’s progression, especially when treatment begins early.
Key points
- A detailed examination of one Alzheimer's patient's brain found that regions cleared of amyloid plaques had little tau accumulation, while nearby uncleared regions had much more tau and neurodegeneration.
- The patient, diagnosed with mild cognitive impairment in his fifties, received 30 doses of aducanumab in a clinical trial and died about four years after his last dose.
- Researchers from the University of Pennsylvania presented the findings at the 2026 Alzheimer's Association International Conference and published them in JAMA.
A rare, detailed study of a single Alzheimer's patient's brain has revealed a sharp divide between areas where treatment removed amyloid plaques and areas where plaques remained. The cleared regions had little or no buildup of tau tangles, a protein strongly linked to brain cell damage and memory decline. Nearby regions that still contained amyloid showed much higher tau levels and signs of ongoing neurodegeneration.
The findings, from researchers at the Perelman School of Medicine at the University of Pennsylvania, were presented at the 2026 Alzheimer's Association International Conference and published in JAMA. The results suggest that thoroughly clearing amyloid, especially early in the disease, may help limit tau accumulation and slow brain damage.
A Rare Brain Examination
The brain tissue came from a former Alzheimer's clinical trial participant. He was in his fifties when diagnosed with mild cognitive impairment caused by Alzheimer's disease. He joined a trial testing aducanumab and received 30 doses over four and a half years. He died about four years after his last dose, more than a decade after his first symptoms, and had wished to donate his brain to research.
Specialists found that the raised ridges of the brain's folded surface, called gyri, had lost most of their amyloid and contained very little tau. The neighboring grooves, or sulci, still had considerable amyloid buildup, along with substantially more tau tangles, inflammation and tissue degeneration. This pattern matched scans taken while the patient was alive.
Seeing both disease patterns side-by-side in the same brain gave us a rare opportunity to understand how amyloid removal affects other proteins that contribute to Alzheimer's disease
— David Wolk, MD
What Researchers Said
Co-senior author David Wolk, MD, of the Penn Memory Center, said the side-by-side view offered a rare chance to understand how amyloid removal affects other proteins tied to Alzheimer's. He said the findings provide some of the clearest human evidence to date that anti-amyloid therapies may limit tau accumulation and slow the brain changes behind memory loss and cognitive decline.
Co-senior author Edward B. Lee, MD, PhD, described the case as a "Goldilocks" scenario in which some regions cleared amyloid and others did not. First author Christopher A. Brown, MD, PhD, said removing amyloid early may help limit the changes that ultimately damage brain cells, and that ongoing trials will help determine whether starting treatment before symptoms begin offers even greater benefit.
