Heterogeneity of intrinsic biophysical properties among cochlear nucleus neurons improves the population coding of temporal information
Heterogeneity of intrinsic biophysical properties among cochlear nucleus neurons improves the population coding of temporal information
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DOI：
10.1152/jn.00836.2013
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发表时间：
2014-06-01
影响因子：
2.5
通讯作者：
MacLeod, K. M.
中科院分区：
文献类型：
--
作者：
Ahn, J.;Kreeger, L. J.;MacLeod, K. M.
声刺激的谱时特征的可靠表示对于声音识别是至关重要的。然而，如果所有的神经元对相同的刺激都有相同的反应，那么活动模式中的冗余将降低群体的信息容量。因此，我们研究了尖峰的可靠性和时间波动编码的神经元在体外记录从鸟类听觉脑干的合奏。连续膜片钳记录从耳蜗角状核的神经元，同时注入相同的过滤高斯白色噪声电流，模拟突触驱动。接受这些相同波动刺激的神经元中的尖峰活动高度相关，在神经元之间成对测量并作为伪种群。两个不同的不相关的噪声刺激可以区分使用的时间模式，但不发射率，在神经合奏的尖峰列车，最好的歧视使用的信息在5-20毫秒的时间尺度。尽管高的互相关值，在个别神经元观察到的尖峰模式是特质的，与显着的异质性在神经元。为了研究时间信息是如何被编码的，我们使用最优线性重建来产生对来自尖峰序列的原始电流刺激的估计。在整个神经群体中采样的训练的集合可以用于使用最佳线性解码来预测>50%的刺激变化，相比之下，使用从单个神经元记录的相同数量的尖峰训练来预测20%。我们的结论是，耳蜗核神经元的内在生物物理特性的异质性降低了发射模式的冗余，同时增强了时间信息的表示。
Reliable representation of the spectrotemporal features of an acoustic stimulus is critical for sound recognition. However, if all neurons respond with identical firing to the same stimulus, redundancy in the activity patterns would reduce the information capacity of the population. We thus investigated spike reliability and temporal fluctuation coding in an ensemble of neurons recorded in vitro from the avian auditory brain stem. Sequential patch-clamp recordings were made from neurons of the cochlear nucleus angularis while injecting identical filtered Gaussian white noise currents, simulating synaptic drive. The spiking activity in neurons receiving these identically fluctuating stimuli was highly correlated, measured pairwise across neurons and as a pseudo-population. Two distinct uncorrelated noise stimuli could be discriminated using the temporal patterning, but not firing rate, of the spike trains in the neural ensemble, with best discrimination using information at time scales of 5-20 ms. Despite high cross-correlation values, the spike patterns observed in individual neurons were idiosyncratic, with notable heterogeneity across neurons. To investigate how temporal information is being encoded, we used optimal linear reconstruction to produce an estimate of the original current stimulus from the spike trains. Ensembles of trains sampled across the neural population could be used to predict >50% of the stimulus variation using optimal linear decoding, compared with similar to 20% using the same number of spike trains recorded from single neurons. We conclude that heterogeneity in the intrinsic biophysical properties of cochlear nucleus neurons reduces firing pattern redundancy while enhancing representation of temporal information.