Variations of telencephalic development that paved the way for neocortical evolution

Area of Science:

• Evolutionary developmental biology
• Comparative neuroanatomy
• Paleontology

Background:

• The mammalian neocortex is a defining feature, crucial for higher cognitive functions.
• Understanding its evolutionary origins requires examining the development of the pallium, the neocortex's precursor.

Purpose of the Study:

• To review variations in pallial development that led to the six-layered neocortex.
• To propose that accumulated subtle modifications in early brain development drove neocortex evolution.

Main Methods:

• Comparative analysis of pallial development in sauropsids and mammals.
• Focus on cell lineage and developmental trajectories.
• Review of gene expression, hodology, and neuronal properties.

Main Results:

• Early differences in morphogen expression influence pallial proportions and organization.
• Varied progenitors and germinative zones generate diverse neuronal populations.
• Taxon-specific neuronal migration patterns shape brain structure and connectivity.

Conclusions:

• Subtle modifications in early development are fundamental to neocortex evolution.
• Cellular origin and developmental pathways are key to understanding evolutionary changes in the pallium.
• Comparative studies of homologous pallial sectors reveal the evolutionary trajectory towards the mammalian neocortex.