Cortical responses to cochlear implant stimulation: Channel interactions
Cortical responses to cochlear implant stimulation: Channel interactions
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DOI：
10.1007/s10162-003-3057-7
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发表时间：
2004-03-01
影响因子：
2.4
通讯作者：
Middlebrooks, JC
中科院分区：
文献类型：
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作者：
Bierer, JA;Middlebrooks, JC
本研究探讨了通过人工耳蜗植入体的两个通道呈现的电刺激之间的相互作用。实验在麻醉的豚鼠中进行。从听觉皮层记录的多单位尖峰活动反映了耳蜗中电场相互作用的累积效应以及沿听觉上行通路沿着的任何神经相互作用。通过6电极耳蜗内阵列电刺激耳蜗。每个通道上的刺激是单个80 μ s/相双相脉冲。通道相互作用被量化为皮层尖峰频率升高阈值的变化。实验参数为通道间时间偏移（0至+/-2000 μ s）、电极间耳蜗间距（1.5或2.25 mm）、电极配置（单极、双极或三极）和通道间的相对极性（相同或倒置）。在大多数情况下，在一个通道上出现亚阈值脉冲会降低第二个通道上脉冲的阈值。阈值位移是最大的同时脉冲，但明显的阈值降低可以持续时间偏移高达640 μ s。通道的相互作用与电极配置变化强烈：阈值位移增加的顺序三极，双极，单极的幅度。通道相互作用更大的更近的电极间距。研究结果对人工耳蜗语音处理器的设计具有指导意义。
This study examined the interactions between electrical stimuli presented through two channels of a cochlear implant. Experiments were conducted in anesthetized guinea pigs. Multiunit spike activity recorded from the auditory cortex reflected the cumulative effects of electric field interactions in the cochlea as well as any neural interactions along the ascending auditory pathway. The cochlea was stimulated electrically through a 6-electrode intracochlear array. The stimulus on each channel was a single 80-mus/phase biphasic pulse. Channel interactions were quantified as changes in the thresholds for elevation of cortical spike rates. Experimental parameters were interchannel temporal offset (0 to +/-2000 mus), interelectrode cochlear spacing (1.5 or 2.25 mm), electrode configuration (monopolar, bipolar, or tripolar), and relative polarity between channels (same or inverted). In most conditions, presentation of a subthreshold pulse on one channel reduced the threshold for a pulse on a second channel. Threshold shifts were greatest for simultaneous pulses, but appreciable threshold reductions could persist for temporal offsets up to 640 mus. Channel interactions varied strongly with electrode configuration: threshold shifts increased in magnitude in the order tripolar, bipolar, monopolar. Channel interactions were greater for closer electrode spacing. The results have implications for design of speech processors for cochlear implants.