Discharge properties of identified cochlear nucleus neurons and auditory nerve fibers in response to repetitive electrical stimulation of the auditory nerve
Discharge properties of identified cochlear nucleus neurons and auditory nerve fibers in response to repetitive electrical stimulation of the auditory nerve
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DOI：
10.1007/s00221-003-1619-x
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发表时间：
2003-12-01
影响因子：
2
通讯作者：
Rouiller, EM
中科院分区：
文献类型：
--
作者：
Babalian, AL;Ryugo, DK;Rouiller, EM
利用29℃的离体豚鼠全脑制备，对耳蜗核（CN）神经元和听神经（AN）纤维进行细胞内记录和染色。以每秒100 - 1000次脉冲（pps）的速率向脑神经网络发送50毫秒的电脉冲，测试脑神经细胞和脑神经轴突的放电特性。在低刺激率（200-300 pps）下，脑神经纤维和腹侧耳蜗核（VCN）的大部分主细胞（丛状、章鱼状、星状）的放电以高概率跟随每个脉冲，导致大量脑神经纤维和脑神经细胞的放电同步。相比之下，在高刺激率（500pps或更高）下，AN纤维和许多VCN细胞表现出“原发样”、“发作”和其他一些类似于自然声音刺激产生的放电模式。与VCN中的细胞不同，背CN的主细胞（锥体、巨细胞）即使在低速率下也不跟随刺激脉冲。相反，它们经常表现出“暂停”和“积聚”的活动模式，这是这些细胞在正常听力条件下的特征。我们假设，在低刺激率下，AN纤维和VCN细胞的反应行为不同于与正常听觉处理相关的神经元活动模式，而高刺激率会产生更有生理意义的放电模式。在不同刺激速率下观察到的AN纤维和CN细胞放电特性的差异，有助于现代人工耳蜗中用于编码声音的高速率电刺激与低速率电刺激的显著优势。
Using the in vitro isolated whole brain preparation of the guinea pig maintained at 29degreesC, we intracellularly recorded and stained cochlear nucleus (CN) neurons and auditory nerve (AN) fibers. Discharge properties of CN cells and AN axons were tested in response to 50-ms trains of electrical pulses delivered to the AN at rates ranging from 100 to 1000 pulses per second (pps). At low stimulation rates (200-300 pps), the discharges of AN fibers and a large proportion of principal cells (bushy, octopus, stellate) in the ventral cochlear nucleus (VCN) followed with high probability each pulse in the train, resulting in synchronization of discharges within large populations of AN fibers and CN cells. In contrast, at high stimulation rates (500 pps and higher), AN fibers and many VCN cells exhibited 'primary-like', 'onset' and some other discharge patterns resembling those produced by natural sound stimuli. Unlike cells in the VCN, principal cells (pyramidal, giant) of the dorsal CN did not follow the stimulating pulses even at low rates. Instead, they often showed 'pauser' and 'build-up' patterns of activity, characteristic for these cells in conditions of normal hearing. We hypothesize that, at low stimulation rates, the response behavior of AN fibers and VCN cells is different from the patterns of neuronal activity related to normal auditory processing, whereas high stimulation rates produce more physiologically meaningful discharge patterns. The observed differences in discharge properties of AN fibers and CN cells at different stimulation rates can contribute to significant advantages of high- versus low-rate electrical stimulation of the AN used for coding sounds in modern cochlear implants.