Circuit properties generating gamma oscillations in a network model of the olfactory bulb
Circuit properties generating gamma oscillations in a network model of the olfactory bulb
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DOI：
10.1152/jn.01141.2005
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发表时间：
2006-04-01
影响因子：
2.5
通讯作者：
Lledo, PM
中科院分区：
文献类型：
--
作者：
Bathellier, B;Lagier, S;Lledo, PM
嗅觉神经基础的研究对于理解嗅觉和神经计算机制都很重要。在嗅球（OB）中，感觉输入和突触相互作用的空间模式对于处理气味信息至关重要，尽管这种模式本身是不够的。最近的研究表明，气味的表征可能已经在第一个嗅觉中继中分布和动态。越来越多的证据表明，延髓神经元活动的时间结构的功能作用支持这一假设。然而，这种时间结构的详细机制从未被彻底研究过。我们的研究集中在哺乳动物OB中的伽马（40-100 Hz）网络振荡，这是嗅觉刺激引起的延髓活动的时间模式的一种形式。我们使用计算模型结合电生理记录，以调查基本的突触组织的必要性和足够的产生持续的伽马节律。我们发现，在体外获得的伽马振荡的特征与基于侧抑制作为耦合模态的模型的特征相同（即，低不规则发射率和高振荡稳定性）。相反，它们与基于横向兴奋性耦合的模型（即，高的规则点火率和不稳定的振荡）。因此，我们可以通过改变支持侧抑制的抑制事件的动力学来精确地调节振荡频率。此外，无论是理论上还是实验上，逐渐减少GABA能突触传递都会降低中继神经元对感觉输入的同步化程度。因此，我们已经表明，侧抑制提供了一种机制，通过这种机制，气味信息的动态处理可能会在OB回路中进行微调。
The study of the neural basis of olfaction is important both for understanding the sense of smell and for understanding the mechanisms of neural computation. In the olfactory bulb (OB), the spatial patterning of both sensory inputs and synaptic interactions is crucial for processing odor information, although this patterning alone is not sufficient. Recent studies have suggested that representations of odor may already be distributed and dynamic in the first olfactory relay. The growing evidence demonstrating a functional role for the temporal structure of bulbar neuronal activity supports this assumption. However, the detailed mechanisms underlying this temporal structure have never been thoroughly studied. Our study focused on gamma (40-100 Hz) network oscillations in the mammalian OB, which is a form of temporal patterning in bulbar activity elicited by olfactory stimuli. We used computational modeling combined with electrophysiological recordings to investigate the basic synaptic organization necessary and sufficient to generate sustained gamma rhythms. We found that features of gamma oscillations obtained in vitro were identical to those of a model based on lateral inhibition as the coupling modality (i.e., low irregular firing rate and high oscillation stability). In contrast, they differed substantially from those of a model based on lateral excitatory coupling (i.e., high regular firing rate and instable oscillations). Therefore we could precisely tune the oscillation frequency by changing the kinetics of inhibitory events supporting the lateral inhibition. Moreover, gradually decreasing GABAergic synaptic transmission decreased the degree of relay neuron synchronization in response to sensory inputs, both theoretically and experimentally. Thus we have shown that lateral inhibition provides a mechanism by which the dynamic processing of odor information might be finely tuned within the OB circuit.