刺激参数对大鼠上肢运动区皮层运动诱发电位的影响

The impact of stimulus parameters on motor evoked potentials of upper limb motor cortex in rats

目的通过对大鼠上肢运动区皮层不同强度、波宽与频率的电刺激,研究不同刺激参数对运动诱发电位(MEP)潜伏期与波幅的影响。方法 18只雄性SD大鼠随机分为3组,每组6只。给予不同波宽(100、200、300μs)、强度(3、6、9、12、15、18、20mA)与频率(3、5、10、20、40、80、160、320Hz)的皮层直接电刺激,记录MEP的波幅与潜伏期。多元方差分析研究不同强度、波宽、频率对大鼠上肢MEP潜伏期与波幅的影响。结果刺激波宽显著影响大鼠上肢MEP潜伏期(P<0.05)与波幅(P<0.05),但100μs与300μs组间MEP波幅差异无统计学意义(P>0.05)。刺激强度也显著影响MEP潜伏期(P<0.05)与波幅(P<0.05),但当刺激强度大于9mA时潜伏期无显著缩短,刺激强度大于12mA时波幅无显著升高。刺激频率对潜伏期(P=0.913)与波幅(P=1.000)无明显影响。结论直接皮层电刺激诱发大鼠上肢运动区MEP,其波幅与潜伏期受刺激波宽与强度的影响,而不受刺激频率的影响,这将为更好地研究功能区病变对运动功能的影响提供动物实验基础。

Objective To investigate the effects of different stimulation parameters on latency and amplitude of rats motor evoked potential（MEP）by direct electrical stimulation on upper limb motor cortex with different intensity,wave width and frequency.Methods Eighteen male Sprague-Dawley rats were randomly divided into three groups（n=6）,with different wave width（100,200,300μs）,intensity（3,6,9,12,15,18,20 mA）and the frequency（3,5,10,20,40,80,160,320 Hz）direct cortical stimulation being applied,the amplitude and latency of MEP were recorded respectively.The effects of different intensity,wave width and frequency on latency and amplitude of MEP in rats′upper limb were studied by multivariate analysis of variance.Results The latency（P〈0.05）and amplitude（P〈0.05）of MEP were significantly affected by wave width,but there was no significant difference in amplitude between 100μs and 300μs yet（P〈0.05）.Similarly,the stimulus intensity also significantly affected the latency（P〈0.05）as well as amplitude（P〈0.05）.There were no significant changes in latency above 9 mA,and no significant changes in amplitude above 12 mA.On the contrary,the stimulation frequency had no significant effect on latency（P=0.913）as well as amplitude（P=1.000）.Conclusion The amplitude and latency of the upper limb motor area MEP in rats induced by bipolar direct cortical electrical stimulation are affected by the stimulus wave width and intensity,not by the stimulus frequency,which will provide an animal experimental basis for better study of the effects of functional area lesions on motor action.