The Development of Striatal Compartments: From Proliferation to Patches

In single striatal sections, the small patches appear imbedded into the larger matrix compartment, but it is clear from serial section reconstructions that the patches form a continuous labyrinthian compartment through the striatum.

Abstract

The conception of the organization of the striatum has changed in recent times from that of a homogeneous structure to that of a distinctly compartmentalized one. Part of this change is really a question of level of analysis. On a single cell level, morphological studies have demonstrated that the vast majority of striatal cells are of a single medium spiny type (Kemp and Powell, 1971). On a multicellular level, the striatum can be divided into two compartments, the patch and the matrix, which can be differentiated on the basis of several neurochemical and hodological markers. In single striatal sections, the small patches appear imbedded into the larger matrix compartment, but it is clear from serial section reconstructions that the patches form a continuous labyrinthian compartment through the striatum (Graybiel and Ragsdale, 1978). The distribution of the patches can be delineated in the adult by high levels of opiate receptors (Kent et al., 1982; Pert et al., 1976), substance P (Gerfen, 1984; Haber and Watson, 1985), neurotensin (Goedart et al., 1984), and afferents from the prefrontal cortex (Donoghue and Herkenham, 1986, Gerfen, 1984). In complementary fashion, the matrix compartment can be identified in the adult by high levels of somatostatin (Gerfen, 1984), neurotensin receptors (Goedart et el., 1984), acetylcholinesterase (Graybiel, 1984), thalamic terminals from the centromedian parafasicular complex (Herkenham and Pert, 1981), and terminations from neurons located in sensorimotor cortex (Donoghue and Herkenham, 1986).