Role of intraglomerular circuits in shaping temporally structured responses to naturalistic inhalation-driven sensory input to the olfactory bulb
Role of intraglomerular circuits in shaping temporally structured responses to naturalistic inhalation-driven sensory input to the olfactory bulb
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DOI：
10.1152/jn.00394.2014
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发表时间：
2015-05-01
影响因子：
2.5
通讯作者：
Wachowiak, Matt
中科院分区：
文献类型：
--
作者：
Carey, Ryan M.;Sherwood, William Erik;Wachowiak, Matt
哺乳动物的嗅觉是由通过鼻腔吸入空气驱动的动态过程。吸入决定了感觉神经元反应的时间结构，并形成了中枢嗅觉处理的神经动力学基础。嗅球（OB）输出神经元[二尖瓣/簇状细胞（MC）]之间的吸入相关的活动爆发相对于感觉神经元发生了时间上的转变。我们使用受到实验结果高度限制的建模方法研究了OB电路如何塑造MC中吸入驱动的动态特性。首先，我们构建了包含MC的单突触和双突触前馈兴奋、递归抑制和前馈抑制的典型OB回路模型。然后，我们使用实验数据来驱动模型的输入和调整参数;输入来自清醒大鼠自然气味采样（嗅探）期间的感觉神经元反应，并将模型输出与MC对相同嗅探波形采样的气味的反应记录进行比较。这种方法使我们能够确定OB电路功能的时间转换的感觉输入到吸入连接模式的MC尖峰输出。我们发现，现实的输入-输出转换可以独立地实现多个电路，包括前馈抑制缓慢的发病和衰减动力学和并行前馈MC兴奋介导的外部簇状细胞。我们还发现，经常性和前馈抑制有不同的影响MC放电率和吸入相关的响应动力学。这些结果突出了在自然环境中研究神经回路的重要性，并为进一步探索OB网络的信号处理提供了一个框架。
Olfaction in mammals is a dynamic process driven by the inhalation of air through the nasal cavity. Inhalation determines the temporal structure of sensory neuron responses and shapes the neural dynamics underlying central olfactory processing. Inhalation-linked bursts of activity among olfactory bulb (OB) output neurons [mitral/tufted cells (MCs)] are temporally transformed relative to those of sensory neurons. We investigated how OB circuits shape inhalation-driven dynamics in MCs using a modeling approach that was highly constrained by experimental results. First, we constructed models of canonical OB circuits that included mono-and disynaptic feedforward excitation, recurrent inhibition and feedforward inhibition of the MC. We then used experimental data to drive inputs to the models and to tune parameters; inputs were derived from sensory neuron responses during natural odorant sampling (sniffing) in awake rats, and model output was compared with recordings of MC responses to odorants sampled with the same sniff waveforms. This approach allowed us to identify OB circuit features underlying the temporal transformation of sensory inputs into inhalation-linked patterns of MC spike output. We found that realistic input-output transformations can be achieved independently by multiple circuits, including feedforward inhibition with slow onset and decay kinetics and parallel feedforward MC excitation mediated by external tufted cells. We also found that recurrent and feedforward inhibition had differential impacts on MC firing rates and on inhalation-linked response dynamics. These results highlight the importance of investigating neural circuits in a naturalistic context and provide a framework for further explorations of signal processing by OB networks.