Shaping the Neocortex: Radial Glia and Astrocytes in Development and Evolution.

Area of Science:

• Neuroscience
• Evolutionary Biology
• Comparative Genomics

Background:

• Mammalian neocortex expansion, particularly in primates, is key to advanced cognition.
• This expansion involves increased size, neuronal output, and structural adaptations like folding and glial complexity.

Purpose of the Study:

• To review the roles of radial glia (RG) and astrocytes in neocortical expansion and evolution.
• To highlight genetic, epigenetic, and cellular mechanisms driving these changes, especially in primates and humans.

Main Methods:

• Review of comparative transcriptomic and morphological studies.
• Analysis of primate- and human-specific genes.
• Examination of epigenetic regulation and chromatin architecture.

Main Results:

• Primate-specific genes enhance RG proliferation and neurogenesis.
• RG morphology facilitates access to extrinsic signals, boosting proliferation and complexity.
• Astrocytes play roles in cortical folding and brain homeostasis.
• Human astrocytes show unique molecular signatures, metabolic capacity, and morphological complexity.

Conclusions:

• RG and astrocytes are central to neocortical evolution and expansion.
• Cellular innovations, including primate-specific genes and astrocyte adaptations, shaped the modern primate and human brain.