An hypothesis on the early evolution of the development of the isocortex

Brain Research Bulletin
Francisco AboitizJavier López

Abstract

We propose an hypothesis on the evolutionary origin of the unique inside-out developmental gradient of the isocortex, in which deep layers originate before superficial layers. This contrasts with the development of the reptilian cortex, which originates in an outside-in gradient. In mice, a mutated protein, reelin, produces the reeler phenotype, whose cortex has an outside-in neurogenetic gradient like in reptiles. Reelin is normally located in the marginal layer of the developing cerebral cortex, and its normal function has been proposed to be a stop signal that prevents radially migrating cells from moving into the marginal zone. Additionally, mutations on the kinase Cdk5, or in its neuronal-specific activator p35, produce a deficit similar to reeler in that the neurogenetic gradient is outside-in. However, contrary to reeler, in which no cell-sparse layer I is observed, in these mice, a well-defined layer I exists, which suggests that migrating cells respond normally to reelin. Apparently, Cdk5/p35 participate in permitting cortical cells to move across pre-existing (earlier produced) cortical layers, in order to be able to contact reelin once they reach the marginal zone. We suggest that the evolutionary advent of the mamma...Continue Reading

Citations

Nov 19, 2002·Brazilian Journal of Medical and Biological Research = Revista Brasileira De Pesquisas Médicas E Biológicas·F AboitizJ López
Sep 19, 2009·Nature Reviews. Neuroscience·Pasko Rakic
Aug 3, 2019·FASEB Journal : Official Publication of the Federation of American Societies for Experimental Biology·Dennis Dik-Long ChauKwok-Fai Lau
Apr 18, 2003·Brazilian Journal of Medical and Biological Research = Revista Brasileira De Pesquisas Médicas E Biológicas·F Aboitiz, J Montiel
Oct 1, 2011·American Journal of Human Biology : the Official Journal of the Human Biology Council·Enric BufillRafael Blesa

❮ Previous
Next ❯

Related Concepts

Related Feeds

Cell Adhesion Molecules in the Brain

Cell adhesion molecules found on cell surface help cells bind with other cells or the extracellular matrix to maintain structure and function. Here is the latest research on their role in the brain.

Cell Checkpoints & Regulators

Cell cycle checkpoints are a series of complex checkpoint mechanisms that detect DNA abnormalities and ensure that DNA replication and repair are complete before cell division. They are primarily regulated by cyclins, cyclin-dependent kinases, and the anaphase-promoting complex/cyclosome. Here is the latest research.

Ataxia telangiectasia (MDS)

Ataxia telangiectasia is a rare neurodegenerative diseases caused by defects in the ATM gene, which is involved in DNA damage recognition and repair pathways. Here is the latest research on this autosomal recessive disease.

Ataxia telangiectasia

Ataxia telangiectasia is a rare neurodegenerative diseases caused by defects in the ATM gene, which is involved in DNA damage recognition and repair pathways. Here is the latest research on this autosomal recessive disease.