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不同时长的电脉冲高频刺激(high frequency stimulation,HFS)对于脑神经系统具有不同的作用.其中,数秒时长的短促HFS可通过“点燃”效应制作动物癫痫模型,也可以产生长时间保持的突触可塑性变化,而数分钟以上的长时HFS却可以安全地用于临床的深部脑刺激,治疗多种脑疾病.因此推测,持续的HFS可以改变短促刺激产生的效应.为了验证此推测,在大鼠海马CA1区的输入轴突纤维Schaffer侧支上,分别施加5 s和2 min两种时长的100 Hz HFS,并监测刺激结束后下游神经元群体对于单脉冲测试的响应电位,即群峰电位(population spike,PS).结果显示,5 s短HFS结束时会紧跟后放电痫样活动,并且,从测试脉冲诱发的PS幅值和潜伏期可见,短HFS诱导的兴奋性增强可以维持数十分钟.反之,2 min的长HFS结束时紧随之后的是数十秒无发放活动的静息期,而且,PS在数分钟内即恢复到HFS前的基线水平.这些结果表明,长时HFS的后期刺激可以改变前期短促刺激对于下游神经网络的作用,即消除短刺激可能产生的长时程兴奋效应.此发现对于深入了解高频刺激的作用机制、促进深部脑刺激的临床应用具有重要意义.
Different durations of high frequency stimulation (HFS) of electrical impulses have different effects on the brain nervous system, in which short HFS of several seconds can make the animal epilepsy model by the “light” effect and can also produce long-term retention Of synaptic plasticity changes, while long-term HFS of more than a few minutes can be safely used in clinical deep brain stimulation for the treatment of a variety of brain diseases.Thus speculated that sustained HFS can change the effect of short-term stimulation.In order to verify this speculation , 100 Hz HFS of 5 s and 2 min were applied to the Schaffer collateral of the input axon in rat hippocampal CA1 region respectively and the response potential of the downstream neuron population to single pulse test was monitored after stimulation The population spike (PS) showed that epileptiform activity was followed immediately after the 5-second short HFS and that the short HFS-induced increase in excitability was observable from the PS amplitude and latency induced by the test pulse For a few tens of minutes.Conversely, a 2-minute long HFS ended immediately after a period of dozens of seconds without resting activity, and PS returned to baseline pre-HFS within minutes.These results show that, Long-term HFS post-stimulation can change the short-term stimulation of the downstream neural network, that eliminate short-term stimulus may have long-term excitation effect.This finding is of deeper understanding of the mechanism of high-frequency stimulation, and promote clinical application of deep brain stimulation It is of great significance.