Charting the protomap of the human telencephalon

Area of Science:

• Neuroscience
• Developmental Biology
• Evolutionary Biology

Background:

• The cerebral cortex is organized into distinct functional areas.
• The protomap hypothesis proposes that neural progenitors in the ventricular zone establish a primordial cortical map.
• Positional information is maintained as neurons migrate to the cortical plate, supported by mouse studies.

Purpose of the Study:

• To investigate the extent to which the protomap hypothesis applies to primate brain development.
• To explore differences in cortical arealization between humans and mice.
• To understand the evolutionary basis of human brain complexity and neurodevelopmental diseases.

Main Methods:

• Review of studies examining arealized gene expression in the early developing human telencephalon.
• Comparative analysis of cortical development mechanisms in humans and model organisms (e.g., mice).

Main Results:

• Evidence suggests fundamental shared mechanisms of areal specification between human and mouse brains.
• Subtle but significant differences in human cortical development are identified.
• Human brains exhibit a higher proportion of association cortex and more complex neuron subtypes compared to mice.

Conclusions:

• The protomap hypothesis is partially supported in primate brain development, indicating conserved early patterning.
• Discrepancies highlight unique aspects of human cortical evolution and regionalization.
• Understanding these differences is crucial for insights into cortical evolution and neurodevelopmental disorders.