Development of the human lateral geniculate nucleus: A morphometric and computerized 3D-reconstruction study.

Area of Science:

• Neuroscience
• Developmental Biology
• Human Anatomy

Background:

• The lateral geniculate nucleus (LGN) is crucial for visual information processing in humans.
• Quantitative morphological data on the prenatal human LGN are scarce.
• Understanding LGN development is vital for comprehending visual pathway formation.

Purpose of the Study:

• To investigate the morphology of the human lateral geniculate nucleus (LGN) during the second half of the fetal period.
• To document the developmental timeline of LGN lamination and structural changes.
• To provide quantitative data on LGN growth during prenatal development.

Main Methods:

• Human fetal brains (20-39 postmenstrual weeks) were sectioned serially.
• Celloidin embedding and horizontal plane sectioning (30 μm) were employed.
• Klüver-Barrera staining was used for histological analysis.

Main Results:

• LGN exhibits an oblique axis and ventro-lateral groove by 20-21 weeks, with initial lamination evident.
• Distinct magnocellular and parvocellular layers, forming the six-layered structure, are recognizable from 25 weeks.
• LGN nuclear volume shows exponential growth, and mean neuronal profile area increases linearly with gestational age.

Conclusions:

• The human LGN develops key structural features, including a ventro-lateral groove and initial lamination, around mid-gestation.
• The characteristic six-layered structure is established by the third trimester.
• Postnatal LGN growth follows an exponential trajectory, highlighting rapid developmental changes.