Beta and gamma oscillations in the olfactory system of the urethane-anesthetized rat
Beta and gamma oscillations in the olfactory system of the urethane-anesthetized rat
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DOI：
10.1152/jn.00475.2003
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发表时间：
2003-12-01
影响因子：
2.5
通讯作者：
Haberly, LB
中科院分区：
文献类型：
--
作者：
Neville, KR;Haberly, LB
在哺乳动物嗅球（OB）和梨状皮质（PC）中由气味剂诱导的场电位中，β（清醒大鼠中为15-40 Hz）和γ（50-100 Hz）频率范围内的快速振荡是突出的。虽然伽马振荡已经研究了超过50年，但β振荡只是最近才引起注意，其起源，机制和与伽马的关系尚不清楚。为了解决这些问题，我们研究了气味诱导的反应，在麻醉大鼠的准备非常适合的机制分析。我们发现，这两种振荡可以诱导的气味剂在浓度依赖性的方式。浓度系列和光谱方法的分析表明，β和γ振荡是不同的，而不是谐波相关，表明产生独立的机制。β振荡在OB中间隔小于或等于4 mm的部位是同步的，这是测试的最大距离。相比之下，伽马振荡在一些实验中是同步的，而在另一些实验中是异步的（频率在不同的位置略有不同，导致渐进的相移）。电流源密度分析表明，对于这两种振荡，在OB的场电位产生的颗粒细胞中的突触电流。这两种振荡的影响不同的手术中断的外侧嗅束。这种病变消除了β振荡，而在OB中仍然诱导了γ振荡。我们的研究结果证实了以前的报告，伽马振荡是在OB内产生的，但表明β振荡需要PC的参与。
Fast oscillations in the beta (15-40 Hz in awake rats) and gamma (50-100 Hz) frequency ranges are prominent in field potentials induced by odorants in the mammalian olfactory bulb (OB) and piriform cortex (PC). Whereas the gamma oscillation has been studied for >50 yr, the beta oscillation has attracted attention only recently, and its origin, mechanism, and relationship to gamma are unknown. To address these questions, we have examined responses induced by odorants in the urethane-anesthetized rat-a preparation well-suited for the analysis of mechanisms. We found that both oscillations could be induced by odorants in a concentration-dependent manner. Analysis with a concentration series and spectral methods revealed that the beta and gamma oscillations were distinct and not harmonically related, indicating generation by independent mechanisms. The beta oscillation was synchronous at sites less than or equal to4 mm apart in the OB, the greatest distance tested. In contrast, the gamma oscillation was synchronous in some experiments and asynchronous in others (frequency differed slightly at different sites, resulting in progressive phase shifts). Current source-density analysis indicated that, for both oscillations, the field potentials in the OB were generated by synaptic currents in granule cells. The two oscillations were differently affected by surgical interruption of the lateral olfactory tract. This lesion abolished the beta oscillation, whereas the gamma oscillation was still induced in the OB. Our results confirm previous reports that the gamma oscillation is generated within the OB but indicate that the beta oscillation requires the participation of PC.