MONAURAL AND BINAURAL RESPONSE PROPERTIES OF NEURONS IN THE INFERIOR COLLICULUS OF THE RABBIT - EFFECTS OF SODIUM PENTOBARBITAL
MONAURAL AND BINAURAL RESPONSE PROPERTIES OF NEURONS IN THE INFERIOR COLLICULUS OF THE RABBIT - EFFECTS OF SODIUM PENTOBARBITAL
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DOI：
10.1152/jn.1989.61.2.269
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发表时间：
1989-02-01
影响因子：
2.5
通讯作者：
STANFORD, TR
中科院分区：
文献类型：
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作者：
KUWADA, S;BATRA, R;STANFORD, TR
1. 研究戊巴比妥钠对家兔下丘22个神经元的影响。我们记录了这些神经元对单耳刺激和持续的耳间时差（ITDs）的敏感性变化。单耳刺激是神经元最佳频率或接近最佳频率的音调爆发。通过向两只耳朵传递不同的1hz的音调来改变过渡段，从而产生1hz的双耳节拍。2. 我们通过计算双耳节拍反应的三个测量值来评估神经元的ITD敏感性：复合延迟、特征延迟（CD）和特征相位（CP）。为了获得复合延迟，我们首先通过平均得到周期直方图，显示每个刺激频率在拍频的一个周期内的响应。其次，将周期直方图重新绘制为等效耳间延迟的函数，然后将其平均，得到复合延迟曲线。最后，通过对复合曲线的波峰或波谷拟合抛物线来计算复合波峰或波谷延迟。复合延迟曲线代表神经元响应范围内所有频率的平均响应，峰值反映产生最大响应的耳间延迟。CD和CP是通过回归线与平均耳间相位相对于刺激频率的图的加权拟合来估计的。这条回归线的斜率和相截距分别产生CD和CP的估计。这两个量被认为反映了过渡段灵敏度的机制，这涉及双耳单元上锁相输入的收敛。CD估计两个输入从任何一只耳朵到这个细胞所需的时间差，而CP反映了这个细胞输入的耳间相位差。3. 手术剂量下注射戊巴比妥钠（小于25mg /kg）几乎无一例外地改变了神经元的反应率、反应潜伏期、反应模式和自发活动。大多数这些变化是可预测的，与抑制作用的增强是一致的。例如，如果最早的反应是抑制性的，那么后来的兴奋通常会减少，潜伏期会增加。如果最早的反应是兴奋性的，则这种兴奋的水平不变或略有增强，并且潜伏期的变化很小。4. 神经元的反应模式也以一种可预测的方式发生了变化。例如，具有抑制性停顿的反应可以变为具有较长停顿的反应，也可以变为仅具有发作的反应。（摘要删节为400字）
1. We studied the effects of sodium pentobarbital on 22 neurons in the inferior colliculus (IC) of the rabbit. We recorded changes in the sensitivity of these neurons to monaural stimulation and to ongoing interaural time differences (ITDs). Monaural stimuli were tone bursts at or near the neuron's best frequency. The ITD was varied by delivering tones that differed by 1 Hz to the two ears, resulting in a 1-Hz binaural beat. 2. We assessed a neuron's ITD sensitivity by calculating three measures from the responses to binaural beats: composite delay, characteristic delay (CD), and characteristic phase (CP). To obtain the composite delay, we first derived period histograms by averaging, showing the response at each stimulating frequency over one period of the beat frequency. Second, the period histograms were replotted as a function of their equivalent interaural delay and then averaged together to yield the composite delay curve. Last, we calculated the composite peak or trough delay by fitting a parabola to the peak or trough of this composite curve. The composite delay curve represents the average response to all frequencies within the neuron's responsive range, and the peak reflects the interaural delay that produces the maximum response. The CD and CP were estimated from a weighted fit of a regression line to the plot of the mean interaural phase of the response versus the stimulating frequency. The slope and phase intercept of this regression line yielded estimates of CD and CP, respectively. These two quantities are thought to reflect the mechanism of ITD sensitivity, which involves the convergence of phase-locked inputs on a binaural cell. The CD estimates the difference in the time required for the two inputs to travel from either ear to this cell, whereas the CP reflects the interaural phase difference of the inputs at this cell. 3. Injections of sodium pentobarbital at subsurgical dosages (less than 25 mg/kg) almost invariably altered the neuron's response rate, response latency, response pattern, and spontaneous activity. Most of these changes were predictable and consistent with an enhancement of inhibitory influences. For example, if the earliest response was inhibitory, later excitation was usually reduced and latency increased. If the earliest response was excitatory, the level of this excitation was unaltered or slightly enhanced, and changes in latency were minimal. 4. The neuron's response pattern also changed in a predictable way. For example, a response with an inhibitory pause could either change to a response with a longer pause or to a response with an onset only.(ABSTRACT TRUNCATED AT 400 WORDS)