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  1. Damage to the axon provokes a series of morphologic and biochemical changes in the neuronal cell body; these changes include disruption and dispersion of Nissl bodies (a.k.a. chromatolysis) associated with rearrangement of the cytoskeleton and marked accumulation of intermediate filaments
  2. Chromatolysis is not visible on conventional light microscopy of small neurons or certain large neurons such as the cerebellar Purkinje cells, but changes can be demonstrated in these cells on electron microscopy and immunohistochemistry
  3. Neurons become swollen and lack Nissl bodies, nucleus becomes large and vesicular
  4. Ballooned neurons can be seen in anterior horn motor neurons with normal aging, Pick’s disease, corticobasal degeneration, pellagra, prion disease, Alzheimer’s, ALS, porphyria, and thallium poisoning.


  1. WikiCNS, "Chromatolysis". Accessed on 2008-08-15.
  2. Gray's Anatomy, p.724. Available online at

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