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Anterior Corticospinal Tract Revisited: A Study Using Human Fetuses
Zhe Wu Jin1, Kwang Ho Cho, Hyung Suk Jang
1Department of Anatomy, Histology and Embryology, Yanbian University Medical College, Yanji, China.
Pediatric Neurosurgery
|February 13, 2016
Summary
The anterior corticospinal tract (CST) develops later than the lateral CST in human fetuses, showing significant individual variations. Its function may involve remodeling ascending tracts rather than direct cortical input to motor neurons.
Area of Science:
- Neuroscience
- Developmental Biology
- Human Anatomy
Background:
- The human corticospinal tract (CST) is crucial for motor control.
- While the lateral CST is well-defined, the fetal development of the anterior CST is poorly understood.
Purpose of the Study:
- To investigate the developmental timeline and morphological variations of the anterior and lateral CST in human fetuses.
- To compare the development of the anterior and lateral CST during fetal stages.
Main Methods:
- Histological examination of horizontal cervical spinal cord sections from midterm (12-18 weeks) and late-stage (28-30 weeks) human fetuses.
- Immunohistochemical analysis to assess macrophage infiltration and radial glial fiber arrangement.
Main Results:
- The lateral CST was observed by 14-15 weeks gestation.
- The anterior CST appeared later (around 15-18 weeks) and showed significant individual variations in presence and thickness in late-stage fetuses.
- The anterior CST's cross-sectional area could reach up to 40% of the lateral CST, with morphological variability between cervical segments.
Conclusions:
- Anterior CST development initiates later than the lateral CST and exhibits considerable inter-individual variability.
- The anterior CST's morphology is dynamic during development, unlike the stable lateral CST.
- The functional role of the anterior CST may be linked to the remodeling of ascending tracts, not solely direct cortical innervation of motor neurons.