Alzheimer's disease (AD) is among the most common cause of dementia in elderly people. Although the causes of AD are not fully understood, abnormal production of the protein beta-amyloid are thought to cause the formation of clumps (called amyloid plaques) in the brain, which kill neurons. In the November issue of Nature Neuroscience, Wen-Biao Gan and colleagues use state-of-the-art imaging techniques to visualize the neuronal damage caused by these amyloid plaques.
The authors use transcranial two-photon imaging to study the degree of neuronal abnormalities near fibrillar amyloid deposits in a transgenic mouse model of AD. They report that dendrites passing through or in the vicinity of these fibrillar amyloid deposits show a loss of spines, along with a general atrophy of the dendritic shaft. Axons are also affected, with axons close to the plaques developing large swellings. These local abnormalities eventually lead to a gradual elimination of many neuronal branches, and a general shortening of neuronal projections. The study shows that amyloid deposition can lead to permanent and global disruption of synaptic connections, which could in turn, be partly responsible for causing the dementia seen in Alzheimer's patients.
Wen-Biao Gan (New York University School of Medicine, New York, NY, USA)
Tel: +1 212 263 2585
Also available online.
(C) Nature Neuroscience press release.
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