Anderson B J, Alcantara A A, Greenough W T
Department of Psychology, University of Illinois, Urbana 61801, USA.
Neurobiol Learn Mem. 1996 Sep;66(2):221-9. doi: 10.1006/nlme.1996.0062.
Rats trained on motor-skill learning tasks for 30 days were previously found to have more synapses in the volume of tissue proportional to a Purkinje cell than rats that exercised or were inactive. In the motor learning tasks, hooded rats were required to traverse an obstacle course requiring balance and coordination. Rats in two exercise groups were required to walk rapidly or allowed to run in activity wheels. Controls were relatively inactive in standard housing and handled once daily. Synapses were classified to determine which synaptic types changed in number across levels of the molecular layer in the paramedian lobule. The motor learning group had significantly more parallel fiber synapses and climbing fiber synapses per unit Purkinje cell reference volume than all other groups. There were also more synapses and more parallel fiber synapses per reference volume in the outermost than in the innermost molecular layer. The plasticity reported here occurs in vivo under normal physiological conditions. Excitatory synapses account for at least 80% of the synapses in the molecular layer. The results support prior predictions that parallel fiber synapses are modifiable during conditions of learning.
先前发现，经过30天运动技能学习任务训练的大鼠，与进行锻炼或不活动的大鼠相比，其浦肯野细胞组织体积中的突触更多。在运动学习任务中，带帽大鼠需要穿过一个需要平衡和协调能力的障碍课程。两个运动组的大鼠被要求快速行走或在活动轮中奔跑。对照组在标准饲养环境中相对不活动，每天处理一次。对突触进行分类，以确定在旁正中小叶分子层各水平上哪些突触类型的数量发生了变化。运动学习组每单位浦肯野细胞参考体积中的平行纤维突触和攀爬纤维突触明显多于所有其他组。最外层分子层每参考体积中的突触和平行纤维突触也比最内层分子层更多。此处报道的可塑性发生在正常生理条件下的体内。兴奋性突触至少占分子层突触的80%。这些结果支持了先前的预测，即平行纤维突触在学习条件下是可改变的。
