BACKGROUND: The afferent projections of the striatum (caudate nucleus and putamen) are segregated in three territories: associative, sensorimotor and limbic. Striatal interneurons are in part responsible for the integration of these different types of information. Among them, GABAergic interneurons are the most abundant, and can be sorted in three populations according to their content in the @entity460 binding proteins calretinin (CR), @entity15537 ( @entity15537 ) and calbindin (CB). Conversely, striatal dopaminergic cells (whose role as interneurons is still unclear) are scarce. This study aims to analyze the interneuron distribution in the striatal functional territories, as well as their organization regarding to the striosomal compartment. METHODOLOGY/PRINCIPAL FINDINGS: We used immunohistochemical methods to visualize CR, @entity15537 , CB and @entity669 hydroxylase (TH) positive striatal neurons. The interneuronal distribution was assessed by stereological methods applied to every striatal functional territory. Considering the four cell groups altogether, their density was higher in the associative (2120  91 cells/mm(3)) than in the sensorimotor (959  47 cells/mm(3)) or limbic (633  119 cells/mm(3)) territories. CB- and TH-immunoreactive(-ir) cells were distributed rather homogeneously in the three striatal territories. However, the density of CR and @entity15537 interneurons were more abundant in the associative and sensorimotor striatum, respectively. Regarding to their compartmental organization, CR-ir interneurons were frequently found in the border between compartments in the associative and sensorimotor territories, and CB-ir interneurons abounded at the striosome/matrix border in the sensorimotor domain. CONCLUSIONS/SIGNIFICANCE: The present study demonstrates that the architecture of the @entity1 striatum in terms of its interneuron composition varies in its three functional territories. Furthermore, our data highlight the importance of CR-ir striatal interneurons in the integration of associative information, and the selective role of @entity15537 -ir interneurons in the motor territory. On the other hand, the low density of dopaminergic cells casts doubts about their role in the normal @entity1 striatum.

Distribution of GABAergic interneurons and dopaminergic cells in the functional territories of the XXXX striatum.

@entity1 :: ('9606', 'Species') :: ['human'] @entity669 :: ('CHEBI:18186', 'Chemical') :: ['tyrosine'] @entity15537 :: ('5816', 'Gene') :: ['parvalbumin', 'PV'] @entity460 :: ('MESH:D002118', 'Chemical') :: ['calcium']
@entity1 :: (9606,Species) :: ['human']
