Abstract
A stereotaxic method of tissue sampling has been developed permitting detailed studies of the distribution of choline acetyltransferase (CAT) in brains from controls and from patients suffering from Huntington's chorea. The characteristic pattern of CAT distribution within extra-pyramidal structures is described. In Huntington's chorea, CAT is unevenly reduced in several brain regions particularly in the rostromedial part of the caudate nucleus. The results indicate a preferential degeneration of neostriatal cholinergic neurones in Huntington's chorea.