重复电刺激前肢神经引起成年大鼠运动皮层的可塑性改变

Plasticity of Motor Cortex Induced by Repetitive Electrical Stimulation of Forelimb Nerve in Adult Rats

为了了解成年大鼠运动皮层（ＭＩ）的功能可塑性，利用皮层内微刺激方法测定ＭＩ代表区并观察重复电刺激前肢神经对ＭＩ代表区的影响。实验组大鼠（９例）持续１．５～２小时的前肢神经电刺激导致前肢运动区（ＦＬ）与面部触须运动区（ＶＩ）边界向ＶＩ方向移动２６３．３±９０．９μｍ（Ｍ±ＳＤ）并同时伴有运动阈值（ＭＴ）的改变：ＦＬ内ＭＴ降低５．０±１３．３μＡ，而在ＶＩ内ＭＴ升高９．６±１１．６μＡ（Ｐ均＜０．０１）。对照组大鼠（６例）间隔１．５～２小时的两次测定结果，ＦＬ－ＶＩ边界移动为２９．７±４３．２μｍ，ＭＴ无明显改变。这一结果表明体表转入输入的改变可快速地引起ＭＩ神经元输出特性的改变。

his study was undertaken to examine if the representational pattern in theprimary motor cortex could be altered by peripheral nerve stimulation. Intracorticalmicrostimuation technique was used to define the forelimb zone(FL) and the adjacentvibrissa zone(VI)in adult Wistar rats under ketamine anaesthesia. It was found thatfollowing 1.5～2hr forelimb nerve stimulation,the FL-VI border shifted substantia- lly towards VI(mean 263μm). Besides,a fall in the motor thresholds(MT)of neuronswithin FL along with a rise in MT of neurons within VI were also noticed,the re-sults indicate that functional reorganization could rapidly occur following altera-tion in afferent input. The possible mechanism involved is disccuscd.