Prenatal development of the human entorhinal cortex.

Area of Science:

• Neuroscience
• Developmental Biology
• Neuroanatomy

Background:

• The human entorhinal cortex (EC) is crucial for learning, memory, and spatial navigation.
• Its early development and cellular organization remain poorly understood.

Purpose of the Study:

• To investigate the early cytoarchitectural and neurochemical development of the human entorhinal cortex.
• To determine the developmental timeline and key cellular events in EC formation.

Main Methods:

• Analysis of 20 fetal and 2 adult human brains.
• Histological techniques: Nissl stain, acetylcholinesterase (AChE) histochemistry.
• Immunocytochemistry for myelin basic protein (MBP), NeuN, neurofilament marker, and synaptophysin.
• Postmortem 3T MRI.

Main Results:

• EC cytoarchitectural differentiation begins by the 10th week of gestation.
• Layer II stellate cells are pivotal for EC lamination, refuting an inside-out development pattern.
• Key developmental milestones, including lamina dissecans formation and perforant path myelination, were observed.
• Adult-like EC organization is achieved by 20 weeks gestation.

Conclusions:

• Early EC development is characterized by a distinct timeline and the crucial role of layer II cells.
• Neurochemical development parallels structural changes, offering insights into EC function.
• These findings have implications for understanding cognitive functions and neurological disorders affecting the EC.