Possible remodeling of the callosal fibers affected by the callosotomy

采用改良高尔基-考克斯法和激光扫描显微镜观察30 ~ 60日龄幼龄小鼠脑胼胝体切开后第1、6、10、12天大脑皮层运动区第3、5层锥体神经元顶端树突棘数的变化。用刀片切开胼胝体前部，包括骨喙、膝和胼胝体体干。锥体神经元顶端树突及其斜支棘的数目，在第3层锥体神经元为第2层水平，在第5层锥体神经元为第3层水平。胼胝体切开术后10 d，这些树突部位的棘密度均增加；脊柱茎和树突的直径也有所增加。然而，这些变化似乎是短暂的，因为它们在胼胝体切开术后第12天几乎下降到正常水平。

Changes in the number of spines on apical dendrites of pyramidal neurons in layrs III and V of the motor area of the cerebral cortex were examined in the young adult mice (30-60 days old) by a modified Golgi-Cox method and laser scanning microscopy on the 1st, 6th, 10th and 12th days after callosotomy. The anterior part of the callosal body, including rostrum, genu and truncus corporis callosi, was sectioned with a razor blade. The numbers of spines on apical dendrites and their oblique branches of pyramidal neurons were counted at the level of layr II for layr III pyramidal neurons and at the level of layr III for layr V pyramidal neurons. The density of spines was increased on all these dendritic parts during 10 days after callosotomy ; the diameters of spine stems and dendrites were also increased. There changes, however, appeared to be transient as they were decreased almost to normal level on the 12th day after callosotomy.