Martin Claire, Ravel Nadine
Laboratory Imagerie et Modélisation en Neurobiologie et Cancérologie, CNRS UMR 8165, Université Paris Sud, Université Paris Diderot Orsay, France.
Team "Olfaction: Du codage à la mémoire," Centre de Recherche en Neurosciences de Lyon CNRS UMR 5292, INSERM U1028, Université Lyon 1 Lyon, France.
Front Behav Neurosci. 2014 Jun 23;8:218. doi: 10.3389/fnbeh.2014.00218. eCollection 2014.
Olfactory processing in behaving animals, even at early stages, is inextricable from top down influences associated with odor perception. The anatomy of the olfactory network (olfactory bulb, piriform, and entorhinal cortices) and its unique direct access to the limbic system makes it particularly attractive to study how sensory processing could be modulated by learning and memory. Moreover, olfactory structures have been early reported to exhibit oscillatory population activities easy to capture through local field potential recordings. An attractive hypothesis is that neuronal oscillations would serve to "bind" distant structures to reach a unified and coherent perception. In relation to this hypothesis, we will assess the functional relevance of different types of oscillatory activity observed in the olfactory system of behaving animals. This review will focus primarily on two types of oscillatory activities: beta (15-40 Hz) and gamma (60-100 Hz). While gamma oscillations are dominant in the olfactory system in the absence of odorant, both beta and gamma rhythms have been reported to be modulated depending on the nature of the olfactory task. Studies from the authors of the present review and other groups brought evidence for a link between these oscillations and behavioral changes induced by olfactory learning. However, differences in studies led to divergent interpretations concerning the respective role of these oscillations in olfactory processing. Based on a critical reexamination of those data, we propose hypotheses on the functional involvement of beta and gamma oscillations for odor perception and memory.
行为动物的嗅觉处理，即使在早期阶段，也与与气味感知相关的自上而下的影响密不可分。嗅觉网络（嗅球、梨状皮质和内嗅皮质）的解剖结构及其与边缘系统的独特直接连接，使得研究感觉处理如何通过学习和记忆进行调节特别具有吸引力。此外，早期有报道称嗅觉结构表现出易于通过局部场电位记录捕获的群体振荡活动。一个有吸引力的假设是，神经元振荡将有助于“绑定”远距离结构，以达成统一且连贯的感知。关于这一假设，我们将评估在行为动物嗅觉系统中观察到的不同类型振荡活动的功能相关性。本综述将主要关注两种类型的振荡活动：β（15 - 40赫兹）和γ（60 - 100赫兹）。虽然在没有气味剂的情况下，γ振荡在嗅觉系统中占主导地位，但据报道，β和γ节律都会根据嗅觉任务的性质而受到调节。本综述作者及其他团队的研究为这些振荡与嗅觉学习诱导的行为变化之间的联系提供了证据。然而，研究中的差异导致了关于这些振荡在嗅觉处理中各自作用的不同解释。基于对这些数据的批判性重新审视，我们提出了关于β和γ振荡在气味感知和记忆中的功能参与的假设。
