Oscillation and Temporal Encoding of Olfactory Info

描述(申请人提供)：来自人脑的脑电记录显示了复杂的波形--通常是振荡的--能量在许多不同的频段。这种活动(例如，40赫兹信号的能量)通常是状态相关的，并随受试者的注意力或清醒程度而变化。一些最戏剧性的调节发生在睡眠的不同阶段。这些宏观信号通常代表大量神经元的同步活动，这些神经元周期性地放电，出现在所有哺乳动物、非哺乳动物脊椎动物以及昆虫和软体动物等较小的动物中。然而，这些信号的功能相关性--因此，导致它们的信号--在很大程度上仍然是猜测。目前的工作旨在破译这些神经、分布和协调现象中的一些，并提供对它们存在的功能和计算上的理解。该方法利用了小神经系统(昆虫大脑)的可及性以及这种协调现象在嗅觉回路(昆虫嗅觉系统：触角叶和蘑菇体)中的普遍存在。使用的方法是电生理学(细胞内和多个单一单元记录)和计算(定量分析、模拟)。由于昆虫和哺乳动物的嗅觉回路如此相似，这项工作的潜在回报是更好地理解神经编码、嗅觉表征以及大脑回路中记忆的格式。例如，表示稀疏性的基本问题(即，记忆应该由神经组件的一个大的子集还是小的子集表示)可以直接用今天哺乳动物的大大脑不可能的方式来研究。因此，这项工作对于破译啮齿动物和灵长类动物的记忆回路以及人类大脑使用的编码策略具有重要意义。

DESCRIPTION (provided by applicant): Electroencepholographic recordings from the human brain reveal complicated waveforms - often oscillatory - with energy in many different frequency bands. This activity (e.g., the energy of 40 Hz signals) is usually state-dependent and varies with the subject's attentiveness or wakefulness. Some of the most dramatic modulations occur in the different phases of sleep. These macroscopic signals generally represent the synchronized activity of large numbers of neurons that fire periodically and occur in all mammals, non-mammalian vertebrates and smaller animals such as insects and molluscs. The functional relevance of these signals -thus, of the signals that cause them-remains, however, largely conjectural. The present work is directed at deciphering some of these neural, distributed and coordinated phenomena and at providing a functional and computational understanding of their existence. The approach exploits the accessibility of small nervous systems (insect brains) and the prevalence of such coordinated phenomena in olfactory circuits (insect olfactory system: antennal lobe and mushroom bodies). The methods used are electrophysiological (intracellular and multi-single unit recordings) and computational (quantitative analysis, simulations). Because olfactory circuits in insects and mammals are so alike, the potential payoff of this work is a better understanding of neural coding, olfactory representations and of the format of memories in brain circuits in general. For example, the fundamental problem of representation sparsity (i.e., whether a memory should be represented by a large or small subset of a neural assembly) can be studied directly in ways that are impossible today with the large brains of mammals. This work will thus have relevance to present efforts to decipher memory circuits in rodents and primates and coding strategies used by the human brain.