Early regional specification for a molecular neuronal phenotype in the rat neocortex.

Abstract

The timing of neocortical regional specification was examined using a monoclonal antibody, designated PC3

Cell-Cycle Kinetics of Neocortical Precursors Are Influenced by Embryonic Thalamic Axons

“…Such afferent specification of cortex (Killackey, 1990) is in line with in vivo and in vitro experiments showing that thalamic afferents influence cell survival and differentiation (Repka and Cunningham, 1987;Windrem and Finlay, 1991;Lotto and Price, 1996;Price and Lotto, 1996;Zhou et al, 1999). However, there is also clear evidence that there is a specification of cortical neuron phenotype at the level of the ventricular zone before migration to the cortical plate (Arimatsu et al, 1992;Cohen-Tannoudji et al, 1994;Soriano et al, 1995;Levitt et al, 1997;Miyashita-Lin et al, 1999, Nakagawa et al, 1999.…”

“…Such afferent specification of cortex (Killackey, 1990) is in line with in vivo and in vitro experiments showing that thalamic afferents influence cell survival and differentiation (Repka and Cunningham, 1987;Windrem and Finlay, 1991;Lotto and Price, 1996;Price and Lotto, 1996;Zhou et al, 1999). However, there is also clear evidence that there is a specification of cortical neuron phenotype at the level of the ventricular zone before migration to the cortical plate (Arimatsu et al, 1992;Cohen-Tannoudji et al, 1994;Soriano et al, 1995;Levitt et al, 1997;Miyashita-Lin et al, 1999, Nakagawa et al, 1999.Given the developmental impact of events in the ventricular zone, it is important to know whether they too are influenced by thalamic afferents. Environmental signaling during the final round of mitosis has been shown to be a key event in the specification of the future connectivity of cortical neuroblasts (McConnell and Kaznowski, 1991;Eagleson et al, 1997), and modulation of cell-cycle kinetics contributes to determining areal cytoarchitecture (Dehay et al, 1993;Polleux et al, 1997).…”

Molecular Evidence for the Early Specification of Presumptive Functional Domains in the Embryonic Primate Cerebral Cortex

“…This protomap would initially direct associations among neighboring cortical cells, and it later attracts appropriate inputs, with intrinsic and extrinsic forces collaborating in the final assignment of region-specific properties (Rakic, 1988). In support of this concept, domain-specific molecular markers as well as regional differences in rates of cell division suggest that distinct populations of cells exist within the cerebral cortex (Barbe and Levitt, 1991;Arimatsu et al, 1992;Dehay et al, 1993;CohenTannoudji et al, 1994;Bulfone et al, 1995;Eagleson et al, 1997;Polleux et al, 1997;Na et al, 1998;Nothias et al, 1998). Furthermore, tissue culture, cell lineage, and transplantation studies testify that cortical cells exhibit certain phenotypic, laminar, and regional biases (Luskin et al, 1988;McConnell, 1988;Parnavelas et al, 1991;Ferri and Levitt, 1993;Tan et al, 1998).…”

The radial edifice of cortical architecture: From neuronal silhouettes to genetic engineering

“…The evidence supporting intrinsic specification of cortical maps (or protomap) has over the years accumulated in numerous reports showing that a selective families of genes and morphoregulatory molecules are expressed in discrete gradients and cortical regions before or independently of the incoming input (Ferri and Levitt, 1993;Nakatsuji et al, 1991;Arimatsu et al, 1992;Simeone, et al, 1992;Gitton et al, 1999;Miyashita-Lin, et al, 1999;Bishop et al, 2000;Sestan et al, 2001;Grove and Fukuchi-Shimogori, 2003;O'Leary and Borngasser, 2006;Cholfin and Rubenstein, 2007; rev in Rubenstein and Rakic 1999). Furthermore, a number of studies in chimeric and transgenic mice have provided direct evidence that the majority of post-mitotic, clonally-related neurons move and remain radially distributed within the intermediate zone and enter only restricted superjacent areas of the cortex (Nakatsuji et al, 1991;Tan and Breen, 1993;Parnavelas et al, 1991;Soriano et al, 1995;Tan et al, 1998;reviewed in Rakic, 1995a).…”