Somatostatin and the patch/matrix compartments of the rat caudate-putamen

In the caudate-putamen of the rat, two subpopulations of medium aspiny neurons exist that contain somatostatin. The first subpopulation contains somatostatin 14, somatostatin 28, and somatostatin 28(1-12). The other subpopulation contains only somatostatin 28. To examine the relationship between somatostatin-containing neurons and the patch/matrix compartments, a series of double-labelling experiments using antisera directed against different somatostatin peptides and calbindin were used. Sections stained in this manner were examined with the aid of a confocal microscope. The results of these experiments indicate that somatostatin 28(1-12)-containing neurons may play a role in matrix integration, with some input directed from the patch compartment. In addition, somatostatin 28-containing neurons are more numerous in the patch compartment than somatostatin 28(1-12)-containing neurons, suggesting a possible role for these neurons in patch integration.