HISTOPATHOLOGIC EVALUATION OF PROLONGED INTRACORTICAL ELECTRICAL-STIMULATION
HISTOPATHOLOGIC EVALUATION OF PROLONGED INTRACORTICAL ELECTRICAL-STIMULATION
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DOI：
10.1016/0014-4886(86)90132-9
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发表时间：
1986-04-01
影响因子：
5.3
通讯作者：
BULLARA, LA
中科院分区：
文献类型：
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作者：
AGNEW, WF;YUEN, TGH;BULLARA, LA
将由铂-30%铱（Pt-30%Ir）或活化铱制成的慢性刺激微电极植入猫的左侧感觉运动皮层中的三个组件中，并以10至320 μ A（100至3200 μ C/cm 2）的电流连续脉冲。ph，2至64 nC/ph），持续24小时或23小时/天，持续7天。微电极具有斜面尖端，其非绝缘几何表面积为20 × 104。10-6 cm2.通过记录同侧嘧啶束的复合动作电位来监测由局灶刺激诱发的神经元活动。根据该标准，神经元激活阈值为5至15 μ A（50至150 μ C/cm 2·cm）。ph，1至3 nC/ph）。对电极头端周围组织进行组织学评价，但采用光学显微镜或电子显微镜。使用任一类型的电极在10至80 μ A的电流下脉冲24或161小时均未诱导神经损伤。在用320 μ A（3200 μ C/cm 2）脉冲的少数部位观察到归因于电刺激本身的神经损伤。ph，64 nC/ph，16 A/cm 2）与Pt-30%Ir，但进入相同尺寸的活化铱电极。电极溶解似乎与电荷密度和电流密度最相关。通过扫描电子显微镜在低至200 μ C/cm 2的电荷密度下观察Pt-30%Ir微电极尖端的溶解。ph（1 A/cm 2），而激活的铱微电极的腐蚀仅在最高电荷和电流密度（3200 μ C/cm 2）下发生。ph，16 A/cm 2）。因此，从电极尖端稳定性的观点来看，活化的铱电极对于慢性刺激上级Pt-30%IR，因为与合金相比，对于前者，仅在远高于激活附近神经元所需的强度时才发生可检测的腐蚀。
Chronic stimulating microelectrodes fabricated from platinum-30% iridium (Pt-30%Ir) or activated iridium were implanted in assemblies of three in the left sensorimotor cortex of the cat and pulsed continously at currents of 10 to 320 .mu.A (100 to 3200 .mu.C/cm2 .cntdot. ph, 2 to 64 nC/ph) for periods of 24 h or for 23 h/day for 7 days. The microelectrodes had beveled tips with uninsulated geometric surface areas of 20 .times. 10-6 cm2. Neuoronal activity evoked by the focal stimulation was monitored by recording compound action potential from the ipsilateral pyrimidal tract. By this criterion neuronal activation thresholds were 5 to 15 .mu.A (50 to 150 .mu.C/cm2 .cntdot. ph, 1 to 3 nC/ph) for both types of electrodes. Histologic evaluations of tissue surrounding the electrode tips were carried but by either light or electron microscopy. No neural damage was induced by 24 or 161 h of pulsing using either type of electrode at currents of 10 to 80 .mu.A. Neural damage attributable to electrical stimulation per se was observed in a few sites pulsed with 320 .mu.A (3200 .mu.C/cm2 .cntdot. ph, 64 nC/ph, 16 A/cm2) with Pt-30%Ir but into activated iridium electrodes of the same size. Electrode dissolution appears to be best correlated with charge density and current density. Dissolution of the Pt-30%Ir microelectrode tip was observed by scanning electron microscopy at charge densities as low as 200 .mu.C/cm2 .cntdot. ph (1 A/cm2), whereas erosion of activated iridium microelectrodes occurred only at the highest charge and current densities (3200 .mu.C/cm2 .cntdot. ph, 16 A/cm2). Thus, the activated iridium electrode is superior to Pt-30%IR for chronic stimulations, from the standpoint of electrode tip stability, because with the former, in contrast to the alloy, detectable erosion occurred only at an intensity well above that required for activation of nearby neurons.