In vitro MRI of brain development

Area of Science:

• Neuroscience
• Developmental Biology
• Radiology

Background:

• The developing human brain exhibits transient structures and zones crucial for normal neurodevelopment.
• Understanding these early stages is vital for identifying potential developmental abnormalities.

Purpose of the Study:

• To elucidate the developmental appearance, structural characteristics, and reorganization of transient cerebral zones and structures in the human fetal brain.
• To correlate histological findings with Magnetic Resonance Imaging (MRI) features during fetal development.

Main Methods:

• Correlative analysis of postmortem aldehyde-fixed human fetal brain specimens (10 postovulatory weeks to term).
• Histological examination to identify cellular and structural features.
• MRI analysis to assess signal intensities and structural visibility of transient zones.

Main Results:

• At 10 weeks, the cerebral wall shows a trilaminar appearance with distinct zones (ventricular, intermediate, cortical plate) and developing structures like the hippocampus and basal ganglia.
• By mid-fetal period (15-22 weeks), typical fetal lamination emerges, with prominent subplate zones rich in extracellular matrix showing low MRI signal.
• Transient MRI features peak between 22-26 weeks due to extracellular matrix and accumulating axons, with blurring of laminar structure by 27-30 weeks.

Conclusions:

• Transient fetal brain zones and subcortical structures exhibit characteristic MRI features.
• These features are attributed to variations in extracellular matrix content, cell packing density, and fiber presence.
• MRI is a valuable tool for visualizing and understanding the dynamic development of the fetal brain.