Early Patterning of Prelimbic Cortical Axons to the Striatal Patch Compartment in the Neonatal Mouse

Abstract

The striatum receives excitatory input from virtually the entire cerebral cortex. In the adult, this input is segregated into two functionally distinct compartments of the striatum, the patch (striosome) and matrix regions. This study determined whether the patterning of corticostriatal afferents from the prelimbic cortex to the striatal patch compartment develops during the early period of collateral formation or instead at the time of peak synaptogenesis. Initial formation of corticostriatal axon collaterals was observed by embryonic day (E) 19. Quantification of corticostriatal collaterals revealed a significant increase in the number and complexity of collateral branches at postnatal day 6 as compared to E19. Concomitant with the increase in collateral branching, a heterogeneous pattern of collateralization consisting of parallel rows of corticostriatal collaterals was observed in the medial striatum. In addition to the rows, clusters of corticostriatal axons occurred more laterally. These clusters colocalized with patches of dense tyrosine hydroxylase-positive fibers, a marker for the striatal patch compartment in the neonatal mouse. Together, these data indicate that corticostriatal patterning occurs during the period of early axon collateralization resulting in a segregation of corticostriatal axon collaterals from the prelimbic cortex to the striatal patch compartment.

Metabotropic Glutamate Receptors mGluR1α and mGluR2/3 Display Dynamic Expression Patterns in Developing Rat Striatum

“…These neuropil patches disappeared by the end of the first postnatal week. Thus, the most intense staining for mGluR1· receptors occurred during elaboration of corticostriatal arborizations [Seth et al, 1998;Nisenbaum et al, 1998]. In parallel to the decrease in neuropil expression, corticostriatal afferents segregate to the striatal patch/striosome compartment by the first postnatal week [Nisenbaum et al, 1998].…”

“…Thus, the most intense staining for mGluR1· receptors occurred during elaboration of corticostriatal arborizations [Seth et al, 1998;Nisenbaum et al, 1998]. In parallel to the decrease in neuropil expression, corticostriatal afferents segregate to the striatal patch/striosome compartment by the first postnatal week [Nisenbaum et al, 1998]. Previous studies have shown glutamate-mediated segregation of specific cortices to target areas during development [Plenz and Kitai, 1998;Furuta and Martin, 1999].…”

Striatal Ionotropic Glutamate Receptor Ontogeny in the Rat

“…Striatal receptors may exert a tropic effect on the innervation of the striatum, helping to attract the cor-Nansen/Jokel/Lobo/Micevych/Ariano/ Levine rect termination of corticopedal fibers. Prelimbic cortex innervated the medial patch compartment by PND 1, while the lateral patches were contacted by PND 3 [Nisenbaum et al, 1998]. This innervation pattern develops after the patchy glutamate receptor subunit staining and remains in place after NMDA R1, Glu R1 and Glu R2/3 staining is distributed evenly in the neuropil.…”

Early Striatal Dendrite Deficits followed by Neuron Loss with Advanced Age in the Absence of Anterograde Cortical Brain-Derived Neurotrophic Factor

“…At P8 there are scattered X-gal-positive cells in somatosensory cortex that become more numerous and cover a wider area caudally. By P15, there is extensive staining in both somatosensory and motor cortices and in all cortical layers, although fewer cells in layer V. Starting at ϳP2, some layer V cortical axon collaterals form connections with striatal neurons (Nisenbaum et al, 1998;Sheth et al, 1998) and thus could provide BDNF to the striatum beginning with the onset of cortical BDNF expression at ϳP4.…”