DELETERIOUS EFFECTS OF PROLONGED ELECTRICAL EXCITATION OF STRIATE CORTEX IN MACAQUES
DELETERIOUS EFFECTS OF PROLONGED ELECTRICAL EXCITATION OF STRIATE CORTEX IN MACAQUES
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DOI：
10.1159/000125575
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发表时间：
1977-01-01
影响因子：
1.7
通讯作者：
OVERMAN, WH
中科院分区：
文献类型：
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作者：
BARTLETT, JR;DOTY, RW;OVERMAN, WH
猕猴被训练对通过永久植入纹状体皮质内或其上的电极施加的电刺激作出反应。动物检测这种刺激的阈值电流每天都高度一致，并且在没有电极的组织封装或故意造成的损伤的情况下，无限期保持稳定，迄今为止最长的情况下为38个月。然而，连续刺激1-8小时，产生阈值的升高，这可能是永久的或暂时的，这取决于各种条件。这种损伤的主要原因是通常由于溶液和金属电极之间的低电平电流通过而发生的水解。即使当通过限制电极极化水平或通过使用五氧化二钽电极的电容性刺激来消除水解反应时，阈值的升高通常仍然会随着延长的刺激而发生。然而，在某些情况下，通过适当的控制，2-10倍于阈值水平的有效刺激可以无限期地保持而没有明显的损伤，例如，在一只阈值为290μ A的盲猴中，可以立即对580 μ A，0.2毫秒的刺激脉冲中的80 μ A减少做出反应，该刺激脉冲以50 Hz稳定施加1小时。
Macaques were trained to respond to electrical excitation applied through electrodes permanently implanted within or upon striate cortex. Threshold current for the animal to detect this stimulation was highly consistent from day to day and, in the absence of tissue encapsulation of the electrodes or deliberately inflicted damage, remained stable indefinitely, 38 months in the longest case so far. Stimulating continuously for 1–8 h, however, produces an elevation of threshold, which may be permanent or temporary, depending upon a variety of conditions. A major cause of such injury is the hydrolysis commonly occurring consequent to passage of low-level currents between solutions and metal electrodes. Even when the hydrolytic reaction is eliminated by restricting the level of electrode polarization or by using capacitative stimulation with tantalum pentoxide electrodes, a rise in threshold often still occurs with protracted stimulation. With proper control in some instances, however, effective stimulation at 2–10 times the threshold level could be maintained indefinitely without apparent injury, e.g. in a blind monkey having a threshold of 290µAthat could respond immediately to an 80µAdiminution in 580-µA,0.2-msec stimulus pulses which had been applied steadily for 1 h at 50 Hz.