Neurofibrillary tangles show intrinsic fluorescence and can be imaged with multiphoton microscopy

(in collaboration with Rich Christie and Brad Hyman, Harvard Medical School)

Other lesions characteristic of Alzheimer's disease, the neurofibrillary tangles (NFT's) are the skeletons of dead neurons in which the crosspieces between microtubules are abnormal. Surprisingly, NFT's within human brain specimens obtained at autopsy exhibit an intrinsic fluorescence signal with two photon excitation in the 700 to 800 nm region (a). A representative spectrum (black) from an in situ NFT is shown in (b). As expected, lipofuscin granules were also brightly fluorescent, but have an emission spectrum (grey) that is easily distinguishable from the NFT emission.