Dendritic degeneration and regrowth in the cerebral cortex of patients with Alzheimer's disease.

Biopsy fragments from the frontal cortex of three patients with Alzheimer's disease were studied by electron microscopy. Electron-dense degenerating dendrites were observed in all cortical layers, but more abundantly in layers 3 and 4. Dendrites with lipid-like droplets and others filled with mitochondria were also seen in these two layers. These findings are in keeping with the abnormalities found with Golgi techniques in the dendritic trees of patients with familial forms of Alzheimer's disease, and are similar to the alterations observed in other diseases accompanied by mental changes.