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：空间 码、时间码和随机访问码，其中访问基于 联想的历史。有证据表明， 嗅觉中化学性质不同的响应剂 上皮组织。嗅觉感受器的轴突投射会聚 嗅球肾小球的神经元(Ons)进一步细化了这个空间 图案。时间因素包括突出的30-80赫兹的嗅球 由细胞的抑制电路调节的振荡活动 嗅球。基于昆虫的模型表明，尖峰的时间相对 对这种振荡的编码在气味识别中具有重要意义。然而， 这种时机的产生还没有被很好地理解。这项提议表明 有两个重要的机制造成了延误。外围设备 这些延迟的机制是由于时间的原因导致OR.N激活的滞后 一些气味物质需要克服吸附到鼻壁上 空洞和/或通过粘液扩散并到达 感受器。这些延迟将根据化学性质和 气味浓度。延误的核心机制是所需的时间 用于沿灯泡的切线曲面进行交互，并在 振荡场势在空间中的位相滞后。这项研究 将跟踪气味反应的空间和时间特征 嗅球的场电位和单单位记录。单细胞 录音将区分两种主要的输出细胞类型，二尖瓣和 丛生细胞，我们已经证明它与局部 灯泡的电路。将对数据进行分析以确定时间 嗅球内侧向抑制相互作用的限制。我们 还将明确测试输出单元格参与的可能性 对气味的振荡反应是经验的结果 气味。这些结果将对理解 闻。

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.