The mammalian neocortex new pyramidal neuron: a new conception.

Area of Science:

• Neuroscience
• Evolutionary Biology
• Developmental Biology

Background:

• Mammals evolved a new cerebral cortex (neocortex) and pyramidal neurons for enhanced motor control.
• Early human embryonic development shows a primordial cortical organization similar to primitive vertebrates.

Purpose of the Study:

• To investigate the developmental process of the neocortex and pyramidal neurons in mammals.
• To understand the evolutionary significance of the number of pyramidal cell functional strata in the motor cortex across species.

Main Methods:

• Comparative analysis of neocortical development across mammalian species.
• Histological examination of embryonic and postnatal brain development.
• Correlation of motor cortex complexity with species-specific motor capabilities.

Main Results:

• The neocortex forms from a primordial organization, with new pyramidal neurons incorporated between 8-15 weeks of gestation.
• Pyramidal neurons elongate their apical dendrites to integrate sensory information for motor activity.
• The number of functional strata in the motor cortex correlates with motor capabilities, with humans having six strata.

Conclusions:

• The six-strata human motor cortex represents a significant evolutionary advancement.
• These specialized structures facilitate complex human behaviors like speech, art, and abstract thought.
• The human cerebrum has developed novel motor centers for translating thoughts into actions.