Electrical stimulation of the auditory nerve: Single neuron strength-duration functions in deafened animals
Electrical stimulation of the auditory nerve: Single neuron strength-duration functions in deafened animals
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DOI：
10.1114/1.1355276
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发表时间：
2001-03-01
影响因子：
3.8
通讯作者：
Baxi, JH
中科院分区：
文献类型：
--
作者：
Shepherd, RK;Hardie, NA;Baxi, JH
耳蜗毛细胞的破坏引发听觉神经纤维（ANF）内的退行性变化，包括外周突起的丢失和细胞体的脱髓鞘。这些变化可能会影响电刺激产生动作电位的生物物理过程。我们通过记录下丘中央核（ICC）中的单个神经元来测量急性增强（100%ANF存活）与长期增强耳蜗（类似于15%ANF存活）的强度-持续时间关系。输入/输出功能的22 ICC神经元响应于刺激的听觉神经，使用双相电流脉冲20-1000 μ s/相位。强度-持续时间曲线的推导和发现是相同的一般形式的急性和长期的硬化耳蜗。虽然长期与急性耳蜗肿胀的神经元的基强度增加，但这种增加没有统计学意义（p=0.097）。相反，与膜时间常数相关的时值在长期老化的耳蜗中明显较短（p = 0.004）。这大概反映了动作电位起始部位向直径较大、有大量髓鞘的中央轴突的转移。动作电位产生部位的这些变化对通过耳蜗植入物向ANF递送电荷具有影响。(C)2001生物医学工程学会。
Destruction of cochlear hair cells initiates degenerative changes within auditory nerve fibres (ANFs), including loss of peripheral processes and demyelination of the cell body. These changes are likely to affect the biophysical processes involved in action potential generation to an electrical stimulus. We measured the strength-duration relationship in acutely deafened (100% ANF survival) versus long-term deafened cochleae (similar to 15% ANF survival) by recording from single neurons in the central nucleus of the inferior colliculus (ICC). Input/output functions were constructed for 22 ICC neurons in response to stimulation of the auditory nerve using biphasic current pulses of 20-1000 mus/phase. Strength-duration curves were derived and found to be of the same general form for both acute and long-term deafened cochleae. While there was an increase in rheobase for neurons from long-term versus acute deafened cochleae, this increase was not statistically significant (p=0.097). In contrast, chronaxie-which is related to the membrane time constant-was significantly shorter in the long-term deafened cochleae (p = 0.004). This presumably reflects a shift in the site of action potential initiation to the larger diameter, heavily myelinated central axon as a result of the pathology. These changes in the site of action potential generation have implications for the delivery of charge to ANFs via cochlear implants. (C) 2001 Biomedical Engineering Society.