Interval-integration underlies amplitude modulation band-suppression selectivity in the anuran midbrain
Interval-integration underlies amplitude modulation band-suppression selectivity in the anuran midbrain
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DOI：
10.1007/s00359-003-0467-2
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发表时间：
2003-12-01
影响因子：
2.1
通讯作者：
Rose, GJ
中科院分区：
文献类型：
--
作者：
Edwards, CJ;Rose, GJ
我们研究了无尾两栖动物听觉中脑中“频带抑制”幅度调制选择性的机制。频带抑制神经元对低(5-10赫兹)和高(>；70赫兹)正弦调幅反应良好，但对中频调幅反应较差。慢速率正弦幅度调制的有效性是由于单个脉冲的持续时间较长；当呈现在5-10个脉冲时，短持续时间脉冲(<；10ms)无法引发尖峰S(-1)。每个单元仅在以最佳速率传送阈值数量的脉冲(中位数=3，范围=2-5)后才响应。显著的刺激特征是在细胞特定耐受范围内的连续脉冲间期的数量。这种间隔积分过程可以通过单个长间隔来重置，即使在此之前有超过阈值数目的间隔。这些发现表明，频带抑制单位是间隔整合神经元的一个子集。带抑制神经元与带通间隔整合细胞的不同之处在于具有较低的间隔数阈值和较宽的间隔耐受性。我们认为，这些特性增加了突触后峰的概率，给出了对长持续时间脉冲反应的传入动作电位的特定时间模式，即使它们易于对慢幅度调制做出反应。提供了支持这一结论的模型证据。
We examined the mechanisms that underlie 'band-suppression' amplitude modulation selectivity in the auditory midbrain of anurans. Band-suppression neurons respond well to low (5-10 Hz) and high (> 70 Hz) rates of sinusoidal amplitude modulation, but poorly, if at all, to intermediate rates. The effectiveness of slow rates of sinusoidal amplitude modulation is due to the long duration of individual 'pulses'; short-duration pulses (< 10 ms) failed to elicit spikes when presented at 5-10 pulses s(-1). Each unit responded only after a threshold number of pulses (median = 3, range = 2-5) were delivered at an optimal rate. The salient stimulus feature was the number of consecutive interpulse intervals that were within a cell-specific tolerance. This interval-integrating process could be reset by a single long interval, even if preceded by a suprathreshold number of intervals. These findings indicate that band-suppression units are a subset of interval-integrating neurons. Band-suppression neurons differed from band-pass interval-integrating cells in having lower interval-number thresholds and broader interval tolerance. We suggest that these properties increase the probability of a postsynaptic spike, given a particular temporal pattern of afferent action potentials in response to long-duration pulses, i.e., predispose them to respond to slow rates of amplitude modulation. Modeling evidence is provided that supports this conclusion.