Neuroscientists at King's College London have identified a mechanism behind one of the stranger features of early Alzheimer's disease: instead of losing connections, the brain briefly gains too many. Working in rat brain cells and funded by Alzheimer's Society, the team showed that low levels of the protein amyloid-beta were enough on their own to make neurons hyperconnected, producing a pattern that closely mirrored what has been observed in the brains of people with mild cognitive impairment.
That distinction matters. Amyloid-beta is best known for forming plaques, the sticky clumps that accumulate around neurons in Alzheimer's disease. This work suggests the protein is doing damage well before it reaches plaque-forming quantities, subtly rewiring how brain cells talk to each other while the tissue still looks largely intact.
The finding fits with earlier research showing that the number of synapses between neurons rises in the earliest stages of the disease, and that this increase tracks with mild cognitive impairment in patients. MCI arrives before widespread cell death and memory loss, which makes it the window in which any future treatment would have the best chance of preserving function.
For now this is laboratory work in rat brain cells rather than a finding in people, so it describes a plausible early mechanism rather than a confirmed sequence of events in human disease. Its value lies in narrowing where researchers should look: at the low-level effects of amyloid-beta on connectivity, rather than only at the plaques that appear later.