Physiological Analysis of the Olfactory Projections

描述：（申请人提供） 嗅觉生理学中的一个重要问题是嗅觉的原理， 可以对信息进行编码和分析。候选原则包括： 码、时间码和随机访问码，其中所述访问基于 协会的历史。有证据表明， 嗅觉对不同化学性质气味的反应 上皮嗅感受器轴突投射的会聚 神经元（ORN）的嗅球肾小球进一步细化这一空间 格局时间因素包括一个突出的30 -80赫兹嗅球 振荡活动是由抑制电路调制的 嗅球基于昆虫的模型表明， 这种振荡在编码气味识别中是重要的。但 这个时机的产生还没有得到很好的理解。这一提议表明， 有两个重要的机制造成了延迟。外围 这些延迟的机制是OR.N激活的延迟， 需要某些气味剂来克服鼻壁的吸附 腔和/或通过粘液扩散并到达 受体。这些延迟将根据化学性质而不同， 气味浓度拖延的核心机制是所需的时间 用于沿着灯泡的切向表面的相互作用，并表示为 振荡场电位在空间上的相位滞后。本研究 将跟踪气味反应的空间和时间特征， 嗅球场电位和单个单位记录。单细胞 记录将区分两种主要的输出细胞类型，二尖瓣和 簇状细胞，我们已经证明，这是差异参与局部 灯泡的电路。将对数据进行分析，以确定 限制嗅球内的侧向抑制相互作用。我们 还将明确测试输出细胞参与的可能性， 在对气味的振荡反应中， 气味剂。这些结果对于理解 味道

DESCRIPTION: (provided by applicant) One important issue in olfactory physiology is the principle by which olfactory information may be coded and analyzed. Candidate principles include: a spatial code, a temporal code, and a random access code with the access being based on the history of association. There is evidence of a spatial separation of response ton odorants with different chemical properties in the olfactory epithelium. The convergence of axonal projection from olfactory receptor neurons (ORNs) to olfactory bulb glomeruli further refines this spatial pattern. Temporal factors include a prominent 3 0-80 Hz olfactory bulb oscillatory activity that is modulated by the inhibitory circuits of the olfactory bulb. Models based on insects suggest that timing of spikes relative to this oscillation are significant in coding odorant identity. However, the generation of this timing is not well understood. This proposal suggests that there are delays generated by two important mechanisms. The peripheral mechanism for these delays is the lag in OR.N activation due to the time required for some odorants to overcome sorption onto the walls of the nasal cavity and/or the time required to diffuse through the mucus and reach receptors. These delays will differ according to chemical properties and odorant concentration. The central mechanism for delays is the time required for interaction along the tangential surface of the bulb and is represented in the phase lags of the oscillatory field potential across space. This research will track the spatial and temporal features of odorant responses with olfactory bulb field potential and single unit recordings. Single cell recordings will distinguish between the two major output cell types, mitral and tufted cells, which we have shown to be differentially involved in the local circuitry of the bulb. The data will be analyzed to determine the temporal constraints on lateral inhibitory interactions within the olfactory bulb. We will also explicitly test the possibility that the involvement of output cells in oscillatory responses to an odorant is the result of experience with that odorant. These results will be of importance for understanding the sense of smell.