Extra spike formation in sensory neurons and the disruption of afferent spike patterning
Extra spike formation in sensory neurons and the disruption of afferent spike patterning
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DOI：
10.1016/s0006-3495(03)75075-9
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发表时间：
2003-04-01
影响因子：
3.4
通讯作者：
Devor, M
中科院分区：
文献类型：
--
作者：
Amir, R;Devor, M
初级感觉神经元特有的假单极几何结构可导致背根神经节区域中“额外尖峰”的异位产生，从而潜在地破坏传入信号的保真度。我们已经使用了明确的有髓鞘脊椎动物感觉神经元的模型来研究额外的尖峰形成的位置和机制，以及其对传入冲动模式的扭曲的后果。在索马峰电位延迟和变宽的条件下，额外的峰电位起源于起始段轴突。然后，加宽的索马尖峰重新激发它刚刚通过的膜，引发一个额外的尖峰，向外传播到主要的传导轴突。额外尖峰的形成取决于细胞的几何形状、电兴奋性和最近的冲动活动史。额外的尖峰会增加向脊髓行进的冲动弹幕，但它们也会在外周神经中逆向行进，与正常的顺向尖峰碰撞并阻塞。因此，传入峰电位数没有净增加。然而，额外的尖峰通过增加序列中短和长的尖峰间期的数量而牺牲中间间期，从而使发射更多的断奏。传入锋电位序列的模式也可能发生更复杂的变化，因此传入信号也可能发生更复杂的变化。
The peculiar pseudounipolar geometry of primary sensory neurons can lead to ectopic generation of "extra spikes" in the region of the dorsal root ganglion potentially disrupting the fidelity of afferent signaling. We have used an explicit model of myelinated vertebrate sensory neurons to investigate the location and mechanism of extra spike formation, and its consequences for distortion of afferent impulse patterning. Extra spikes originate in the initial segment axon under conditions in which the soma spike becomes delayed and broadened. The broadened soma spike then re-excites membrane it has just passed over, initiating an extra spike which propagates outwards into the main conducting axon. Extra spike formation depends on cell geometry, electrical excitability, and the recent history of impulse activity. Extra spikes add to the impulse barrage traveling toward the spinal cord, but they also travel antidromically in the peripheral nerve colliding with and occluding normal orthodromic spikes. As a result there is no net increase in afferent spike number. However, extra spikes render firing more staccato by increasing the number of short and long interspike intervals in the train at the expense of intermediate intervals. There may also be more complex changes in the pattern of afferent spike trains, and hence in afferent signaling.