State transition analysis of lineages provides an explicit graphic description of data obtained from numerous lineage trees and reveals complex relationships between OSVZ precursors. One salient characteristic of OSVZ precursor lineage is the occurrence of bidirectional transitions that depart from the

classical unidirectional lineage genealogy, Rapamycin in vitro including that reported in rodent corticogenesis (Noctor et al., 2004, Qian et al., 1998 and Tyler and Haydar, 2013). One can hypothesize that precursor diversity and their complex lineage relationships changing over time reflects a process that allows for the self-organization of the cortex (Kennedy and Dehay, 2012). Although the basic module of five precursor types is present at E65 and E78, the state transition analysis shows that lineage

relationships between precursors show stage-specific differences. Specifically, the present results reveal differences in the topology of lineage state transitions during the generation of infra- and supragranular layer neurons. This provides an innovative conceptual framework 5-Fluoracil mouse for understanding the mechanisms ensuring the ordered production of phenotypically distinct neuronal populations. While it is generally agreed that the Old World macaque monkey is a valid model for understanding many features of the human brain, future comparative studies of a range of different members of the primate order and nonprimates will be necessary in order to better define primate-specific features. Temporal changes in competence have been shown to contribute to the generation of distinct neuronal types in distinct numbers during corticogenesis by a common pool of precursors (Jacob et al., 2008 and Qian et al., 1998). The present results show that, superimposed on these changes in temporal competence, there are modifications in lineage relationships that are consistent

with the observed changes in cell-cycle parameters (Figure 7C). This would imply that the interplay of temporal competence and lineage state transition topology is a widespread developmental mechanism in the CNS (Ulvklo et al., 2012). For numbers of animals, see Supplemental Experimental Procedures. For numbers of hemispheres, slices, and cells, see figure legends. Fetuses from timed-pregnant cynomolgus monkeys (Macaca fascicularis, gestation already period 165 days) were delivered by caesarian section as previously described ( Lukaszewicz et al., 2005). All experiments were in compliance with national and European laws as well as with institutional guidelines concerning animal experimentation. Surgical procedures were in accordance with European requirements 2010/63/UE. The protocol C2EA42-12-11-0402-003 has been reviewed and approved by the Animal Care and Use Committee CELYNE (C2EA 42). Occipital poles of embryonic hemispheres were isolated and embedded in 3% low-melting agarose in supplemented HBSS at 37°C.