Fibers from the basolateral nucleus of the amygdala selectively innervate striosomes in the caudate nucleus of the cat.

The compartmental organization of the amygdalostriatal projection was studied in the cat by comparing staining patterns seen by cholinesterase enzyme histochemistry with the distribution of fibers labelled with a horseradish peroxidase-wheat germ agglutinin conjugate or by incorporation of 35S-methionine or 3H-leucine. Fibers from the basolateral nucleus of the amygdala were found to innervate selectively acetylcholinesterase-poor striosomes demonstrated in the caudate nucleus and butyrylcholinesterase-rich zones observed in the anterodorsal nucleus accumbens. In no case were the amygdalar fibers fully restricted to striosomes, but the nature and degree of labelling of the striatal matrix, as well as the range of the labelled fibers in dorsal striatum, varied with the positions of the injection sites.