The effects of prolonged intracortical microstimulation on the excitability of pyramidal tract neurons in the cat
The effects of prolonged intracortical microstimulation on the excitability of pyramidal tract neurons in the cat
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DOI：
10.1114/1.1430748
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发表时间：
2002-01-01
影响因子：
3.8
通讯作者：
Bullara, LA
中科院分区：
文献类型：
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作者：
McCreery, DB;Agnew, WF;Bullara, LA
本研究旨在研究使用空间密集微电极阵列进行长时间微刺激期间大脑皮质神经元兴奋性的变化。将16个铱微电极阵列长期植入猫的交叉后回。在延髓锥体中记录单个锥体束轴突（ULR）的神经元反应特征。在50 Hz和4 nC/ph下对单个电极进行7 h脉冲处理，ULR的电阈值几乎没有变化或没有变化。当16个微电极中的4个在连续14天的每一天被脉冲时，阈值也相当稳定。然而，当所有16个微电极在4 nC/ph下脉冲7 h时，大约一半的ULR的阈值升高。兴奋性恢复需要2-18天。延长顺序（交错）脉冲的16个微电极诱导抑郁症的兴奋性比同时脉冲，但只有当刺激幅度低（12 A，1.8 nC/ph）。在更高的幅度（15 nC/ph）刺激诱导更多的抑郁症的兴奋性。这些发现意味着多个过程介导的刺激诱导的神经元兴奋性的抑郁症。数据还表明，抑郁症可以通过采用刺激方案来减少，其中阵列的固有空间分辨率被最大化（在有效电流场的重叠最小的幅度下的顺序脉冲）。(C)2002生物医学工程学会。
This study was conducted to examine the excitability changes induced in cerebral cortical neurons during prolonged microstimulation with a spatially dense microelectrodes array. The arrays of 16 iridium microelectrodes were implanted chronically into the postcruciate gyrus of cats. Neuronal responses characteristic of single pyramidal tract axons (ULRs) were recorded in the medullary pyramid. 7 h of pulsing of individual electrodes at 50 Hz and at 4 nC/ph induced little or no change in the ULRs' electrical thresholds. The thresholds also were quite stable when 4 of the 16 microelectrodes were pulsed on each of 14 consecutive days. However, when all 16 microelectrodes were pulsed for 7 h at 4 nC/ph, the threshold of approximately half of the ULRs became elevated. Recovery of excitability required 2-18 days. Prolonged sequential (interleaved) pulsing of the 16 microelectrodes induced less depression of excitability than did simultaneous pulsing, but only when the stimulus amplitude was low (12 A, 1.8 nC/ph). Stimulation at a higher amplitude (15 nC/ph) induced much more depression of excitability. These findings imply that multiple processes mediate the stimulation-induced depression of neuronal excitability. The data also demonstrate that the depression can be reduced by employing a stimulus regimen in which the inherent spatial resolution of the array is maximized (sequential pulsing at an amplitude in which there is minimal overlap of the effective current fields). (C) 2002 Biomedical Engineering Society.