Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 2001 Nov;11(11):1027-39.
doi: 10.1093/cercor/11.11.1027.

Pre- And Post-Mitotic Events Contribute to the Progressive Acquisition of Area-Specific Connectional Fate in the Neocortex

Affiliations
Comparative Study

Pre- And Post-Mitotic Events Contribute to the Progressive Acquisition of Area-Specific Connectional Fate in the Neocortex

F Polleux et al. Cereb Cortex. .

Abstract

The adult primary motor cortex (area 6) is characterized by a stronger projection to the spinal cord than the primary somatosensory cortex (area 3). Here we have explored the progressive and regressive phenomena that determine these areal differences in the number of corticospinal neurons (CSNs). CSNs were birthdated with [(3)H]thymidine and subsequently retrogradely labeled from the spinal cord. The time window of CSN production is identical in both areas. The probability that a cohort of neuroblasts project to the spinal cord is indicated by the percentage of [(3)H]thymidine-positive neurons that can be back-labeled from the spinal cord. In the neonate this fate index is significantly higher in area 6 compared with area 3, indicating that early regionalization of cell fate contributes to areal differences in CSN number. In neonatal reeler mice, an increase in CSN number was accompanied by an increased fate index, showing that the integrity of the post-mitotic environment is required for the specification of the appropriate number of neurons expressing a given connectional phenotype. Postnatal development in reeler and normal is characterized by an area-specific elimination of CSN axons, which reduces areal differences in CSN number. These results show a progressive acquisition of CSN fate in the neocortex and indicate that both early regionalization and late environmental signals contribute to determining areal differences of connectional phenotype.

Similar articles

See all similar articles

Cited by 17 articles

See all "Cited by" articles

Publication types

LinkOut - more resources

Feedback