An improved method for the histopathological evaluation of the substan
tia nigra for diagnostic purposes is proposed. This method takes advan
tage of the natural architecture of the constituent cel clusters of th
e substantia nigra by combining standardized sections in the horizonta
l plane and simple quantification. The use of this standardized techni
que should increase the diagnostic reliability and sensitivity of patt
erns of cell loss within the substantia nigra.