Postnatal development attunes olfactory bulb mitral cells to high-frequency signaling.
Postnatal development attunes olfactory bulb mitral cells to high-frequency signaling.
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出生后发育使嗅球二尖瓣细胞适应高频信号。
DOI：
10.1152/jn.00315.2015
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发表时间：
2015
影响因子：
2.5
通讯作者：
Urban,NathanielN
中科院分区：
文献类型：
--
作者：
Yu,Yiyi;Burton,ShawnD;Tripathy,ShreejoyJ;Urban,NathanielN
二尖瓣细胞(MCs)是脊椎动物嗅球中的一类主要神经元，负责将嗅觉诱发活动从周围感觉神经元传递到嗅皮层。以前的工作已经描述了MC在出生后最初几周的形态和连通性的发展。然而，对于MC固有的生物物理特性在出生后的发展情况却知之甚少。为了了解发育中的嗅球的刺激编码，我们因此研究了出生后7-35天小鼠的急性脑片MC内在生物物理特性的发展。在发育过程中，我们观察到被动膜特性和动作电位波形的系统性变化，这些变化与钠和钾电导的发育增加相一致。我们进一步观察到超极化诱发的膜电位凹陷和放电规律性的发育性降低，延伸了MC凹陷的异质性和放电模式之间的最近联系。然后，我们应用一种新的统计分析组合来研究这些内在生物物理属性的演变如何具体影响MC对波动刺激的表示。我们发现，与成熟的MC相比，未成熟的MC对冰冻波动刺激的反应具有更低的放电频率、更低的尖峰时间可靠性和更低的细胞间尖峰时间相关性。对尖峰触发平均值的分析表明，尖峰计时的这些变化是由从广泛整合输入到更有选择性地检测重合输入的发展转变所推动的。与这一转变相一致的是，适用于MC放电反应的广义线性模型表明，成熟MC对高频刺激特征的编码得到了增强。
Mitral cells (MCs) are a major class of principal neurons in the vertebrate olfactory bulb, conveying odor-evoked activity from the peripheral sensory neurons to olfactory cortex. Previous work has described the development of MC morphology and connectivity during the first few weeks of postnatal development. However, little is known about the postnatal development of MC intrinsic biophysical properties. To understand stimulus encoding in the developing olfactory bulb, we have therefore examined the development of MC intrinsic biophysical properties in acute slices from postnatal day (P)7–P35 mice. Across development, we observed systematic changes in passive membrane properties and action potential waveforms consistent with a developmental increase in sodium and potassium conductances. We further observed developmental decreases in hyperpolarization-evoked membrane potential sag and firing regularity, extending recent links between MC sag heterogeneity and firing patterns. We then applied a novel combination of statistical analyses to examine how the evolution of these intrinsic biophysical properties specifically influenced the representation of fluctuating stimuli by MCs. We found that immature MCs responded to frozen fluctuating stimuli with lower firing rates, lower spike-time reliability, and lower between-cell spike-time correlations than more mature MCs. Analysis of spike-triggered averages revealed that these changes in spike timing were driven by a developmental shift from broad integration of inputs to more selective detection of coincident inputs. Consistent with this shift, generalized linear model fits to MC firing responses demonstrated an enhanced encoding of high-frequency stimulus features by mature MCs.