4.7 Review

Genetic Mechanisms Underlying Cortical Evolution in Mammals

Journal

Publisher

FRONTIERS MEDIA SA
DOI: 10.3389/fcell.2021.591017

Keywords

brain; elephant; cetacea; primates; human; cortex; human accelerated region; synapsids

Funding

  1. Agencia Nacional de Promocion Cientifica y Tecnologica de Argentina (ANPCyT) [PICT-2018-02216]

Ask authors/readers for more resources

The emergenece of the six-layered neocortex in reptilian ancestors of mammals is a key evolutionary event, facilitating the development of remarkable sensory, motor, and cognitive abilities in mammals. Each mammalian lineage exhibits unique genetic programs that contribute to the diversity in neocortical development, potentially leading to differences in brain structure and function across species. The human brain, with its large neocortex, has evolved unique cognitive capacities such as abstract thinking, verbal language, and long-term planning, believed to be a result of the cortical expansion and elaboration of connections in the human lineage.
The remarkable sensory, motor, and cognitive abilities of mammals mainly depend on the neocortex. Thus, the emergence of the six-layered neocortex in reptilian ancestors of mammals constitutes a fundamental evolutionary landmark. The mammalian cortex is a columnar epithelium of densely packed cells organized in layers where neurons are generated mainly in the subventricular zone in successive waves throughout development. Newborn cells move away from their site of neurogenesis through radial or tangential migration to reach their specific destination closer to the pial surface of the same or different cortical area. Interestingly, the genetic programs underlying neocortical development diversified in different mammalian lineages. In this work, I will review several recent studies that characterized how distinct transcriptional programs relate to the development and functional organization of the neocortex across diverse mammalian lineages. In some primates such as the anthropoids, the neocortex became extremely large, especially in humans where it comprises around 80% of the brain. It has been hypothesized that the massive expansion of the cortical surface and elaboration of its connections in the human lineage, has enabled our unique cognitive capacities including abstract thinking, long-term planning, verbal language and elaborated tool making capabilities. I will also analyze the lineage-specific genetic changes that could have led to the modification of key neurodevelopmental events, including regulation of cell number, neuronal migration, and differentiation into specific phenotypes, in order to shed light on the evolutionary mechanisms underlying the diversity of mammalian brains including the human brain.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.7
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available