S-Space College of Medicine/School of Medicine (의과대학/대학원) Dept. of Medicine (의학과) The Seoul Journal of Medicine The Seoul Journal of Medicine Vol. 20 No.4 (1979)
한국인 태아의 중추 신경계 수초화에 관한 연구 : Myelination Cycle of the Developing Human Brains
- Issue Date
- 서울대학교 의과대학
- Seoul J Med, Vol.20 No.3, pp. 268-278
- It is often desirable to know the maturity of the
fetal brains of a wide variety of gestational ages.
Although myelination is known as an important
process of regional maturation of the nervous system,
it is still not clear whether myelination cycle is
stereotypic enough to be a parameter of maturation
in the fetal brains.
We have studied a total of 123 brains and spinal
cords of the Korean fetuses of gestational ages ranging
from 12 to 44 weeks. These fetuses were products of artificial abortion. The brains and spinal cords
were removed as soon as possible after delivery, and
were fixed in 10% formalin. Representative blocks
were taken from standardized portions of the nervous
system. Through routine histological process slides
were made and stained with hematoxylin-eosin and
Luxol-Fast-Blue for general morphology and myelin,
Tables were made to list myelination process of
all the major fiber-systems by different gestational
periods. The listing of a fiber-system was based on
microscopically demonstrated myelin tubules in
certain area in more than half of the cases.
Following conclusions were made.
1. The pattern of myelination in the developing
central nervous system at various gestational periods.
is not strictly stereotyped. However, there is a
definite trend of an orderly process in which functionally
allied systems were synchronized in an orderly
2. As gestation progresses, increasing number of
cells with large pale vesicular nuclei appeared in thearea
to be myelinated, prior to actual deposit of the
material (myelin) stainable with Luxol Fast Blue.
These myelination glial cells decreased gradually
in number as myelination process advanced.
3. The myelination started in the anterior and
posterior nerve roots of the spinal cords at 12 to 15weeks
gestational period. The fiber-system mediating
the general proprioceptive experience myelinates early
and rapidly at 16 to 20 weeks gestational period.
followed by the fiber-system mediating vestibular
and acoustic modalities in the brain stem. Theexteroceptive(
tactile and pain) somatic fiber-system
myelinates later and slowly. These sensory pathways
showed ascending (cephalad) progression of myelination.
The corticospinal tract myelination then rapidly
becomes apparent in a caudal direction through the
brain stem and spinal cord.
4. Stainable myelin was rarely seen in the medullary
substance of the cerebral hemisphere except
along the course of fiber tract of the internal capsule
and optic radiation even in full term fetuses.