Oishi T, Higo N, Umino Y, Matsuda K, Hayashi M
Neuroscience Section, Electrotechnical Laboratory, Ibaraki, Japan.
Brain Res Dev Brain Res. 1998 Jul 1;109(1):87-97. doi: 10.1016/s0165-3806(98)00067-4.
To estimate the extent of axonal growth in various areas of the cerebral cortex, we measured the amount of GAP-43 mRNA in the cerebral cortex of developing macaque monkeys. In four areas, i.e., the prefrontal area (FD delta), the temporal association area (TE), the primary somatosensory area (PC), and the primary visual area (OC), the amount of GAP-43 mRNA was measured from the intermediate fetal period [embryonic day 120 (E120)] to the adult stage. In two other areas, i.e., the parietal association area (PG) and the secondary visual area (OB), the amount of GAP-43 mRNA was measured during the postnatal period. The amount of GAP-43 mRNA was highest at E120, decreased roughly exponentially, and approached the asymptote by postnatal day 70 (P70). The amount of GAP-43 mRNA was higher in the association areas (FD delta, TE, and PG) than in the primary sensory areas (PC and OC) during development and at the adult stage. These findings suggest that axonal growth in the cerebral cortex is most exuberant before or during the intermediate fetal period and approximately ends by P70. Furthermore, axonal growth is evidently more intensive in the association areas than in the primary sensory areas during the stage following the intermediate fetal period.
为了评估大脑皮质各区域轴突生长的程度，我们测量了发育中的猕猴大脑皮质中GAP - 43 mRNA的含量。在四个区域，即前额叶区（FDδ）、颞叶联合区（TE）、初级躯体感觉区（PC）和初级视觉区（OC），从胎儿中期[胚胎第120天（E120）]到成年期测量GAP - 43 mRNA的含量。在另外两个区域，即顶叶联合区（PG）和次级视觉区（OB），在出生后测量GAP - 43 mRNA的含量。GAP - 43 mRNA的含量在E120时最高，大致呈指数下降，并在出生后第70天（P70）接近渐近线。在发育过程中和成年期，联合区（FDδ、TE和PG）中GAP - 43 mRNA的含量高于初级感觉区（PC和OC）。这些发现表明，大脑皮质中的轴突生长在胎儿中期之前或期间最为旺盛，大约在P70时结束。此外，在胎儿中期之后的阶段，联合区的轴突生长明显比初级感觉区更为密集。
