Pathogenesis of four-layered microgyric cortex in man

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Neuropathology

Background:

• Microgyria (polygria, polymicrogyria) is a congenital brain malformation characterized by an increased number of small, abnormally convoluted cerebral gyri.
• Numerous theories exist regarding the pathogenesis of microgyria, primarily based on human case studies and principles of cortical development.

Purpose of the Study:

• To analyze a unique case of bilateral microgyria that presented atypical features not fully explained by existing theories.
• To investigate the pathogenetic mechanisms underlying this specific microgyria presentation.

Main Methods:

• Case study analysis of a patient with bilateral microgyria.
• Histopathological examination utilizing various staining techniques.
• Comparison of findings with established principles of human cortical development and animal models.

Main Results:

• The case exhibited four-layered microgyria bilaterally within the middle cerebral artery distribution.
• A unique finding in one hemisphere was the replacement of deep layers by radially aligned neurons extending ectopically into the white matter.
• These findings align with a recently described pathogenetic mechanism observed in a rat model of microgyria.

Conclusions:

• The observed ectopic neuronal migration in microgyria supports a specific pathogenetic mechanism previously identified in a rat model.
• This case expands our understanding of microgyria formation and its potential underlying mechanisms in humans.