In AThChE stained material, the various territories of the cat brain stem differ from each other according to (a) the greater or lesser degree of stainability and (b) the sharpness with which they are outlined. The duality proposed by Mannen (1960) of “closed” nuclei versus “open” nuclei is as applicable here as in Golgi stained material. Some centers like the inferior olivary complex stand out not only because of their high enzyme content but also because of their strikingly well delimited borderlines. Others, like the superior olivary complex, are equally well delimited but remarkably pale. On the other hand, there are a number of regions, which may be either pale or intensely stained, that display very poorly delimited outlines so that the separation from adjacent areas becomes quite arbitrary. The following account is presented in terms of a working hodological classification of nerve centers. It should be borne in mind, however, that no striking correlations appear to exist between the functional role or hodological order of a given center and its AThChE content. Only general trends and rules subject to notorious exceptions can be suggested.
KeywordsRetina Cholin Acetylcholine Agglomeration Acetyl
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