Mechanisms of processing temporally structured olfactory stimuli

有气味的烟羽中含有各种不同气味的混合物，这些气味不断地被空气中的气味混合在一起。气味强度的波动取决于气味源的距离，来自同一来源的气味（例如，组成花朵气味的不同化学物质）在其强度变化中具有共同的时间结构。因此，分析气味刺激的时间特性可能为动物定位和辨别不同气味源提供关键信息。在这个项目中，我建议结合联合收割机在小鼠的行为，生理和光遗传学实验，以评估这种时间调制的气味是如何表示和discriminated.To隔离气味的质量和强度，从鼻子的感觉输入被传递到嗅球，在那里它是由当地的神经回路处理。颗粒细胞是嗅球中数量最多的中间神经元。它们已经被证明在塑造时间活动中发挥重要作用，包括投射神经元的精确，协调的放电。此外，它们的长树突允许在整个灯泡上进行广泛的信号整合。总之，这使他们成为一个很好的候选人塑造的代表性的时间结构的气味stimulations.The主要目标的这项新研究是阐明颗粒细胞的作用，通过采用嗅觉任务，刺激将呈现在一个复杂的时间结构。我将评估抑制性颗粒细胞对行为表现和刺激表征的影响，使用细胞内记录从清醒的，行为头部固定的小鼠中识别出的投射神经元。我将确定时间结构的个人气味和气味混合物的气味歧视的带宽。使用光遗传学沉默对颗粒细胞活性的急性干扰将使我能够研究颗粒细胞对区分时间结构气味的影响。来自清醒的、行为正常的头部固定的颗粒细胞活动沉默的小鼠的投射神经元的体内生理记录将提供有关颗粒细胞回路对嗅球神经输出的影响的直接信息。Andreas Schaefer教授及其实验室的专业知识，国家他们建立的艺术实验技术和国家医学研究所神经生理学部门的科学环境研究，弗朗西斯克里克研究所和大学学院伦敦，都提供了一个很好的环境，成功地进行这项新的研究。

An odorant plume harbours a mixture of different odours constantly intermingled by air turbulences. Odour intensity fluctuates depending on the distance of an odour source, odours emerging from the same source (such as, say, the different chemicals that make up the smell of a flower) share a common temporal structure in their intensity variations. Thus, analysing the temporal properties of an odour stimulus might provide key information for an animal to locate and discern different odour sources. In this project, I propose to combine behavioural, physiological and optogenetic experiments in mice to assess how such temporally modulated odours are represented and discriminated.To isolate odour quality and intensity, sensory input from the nose is conveyed to the olfactory bulb where it is processed by the local neural circuitry. Granule cells comprise the most numerous type of interneurons in the olfactory bulb. They have been shown to play an important role in shaping temporal activity, including the precise, coordinated firing of projection neurons. Furthermore, their long dendrites allow for widespread signal integration over the entire bulb. Together, this renders them an excellent candidate for shaping the representation of temporally structured odour stimuli.The major goal of this new study is to elucidate the role of granule cells by employing an olfactory task where stimuli will be presented in a complex temporal structure. I will assess the influence of inhibitory granule cells on behavioural performance and stimulus representation using intracellular recordings from identified projection neurons in awake, behaving head-fixed mice. I will determine the bandwidth of odour discrimination for both temporally structured individual odours and odour mixtures. Acute interference in granule cell activity using optogenetic silencing will let me investigate the impact of granule cells on discriminating temporally structured odours. In vivo physiological recordings from projection neurons in awake, behaving head-fixed mice with silenced granule cell activity will provide direct information about the influence of the granule cell circuit on olfactory bulb neural output.The expertise of Prof. Andreas Schaefer and his lab, the state-of-the-art experimental techniques they have established and the scientific environment at the Division of Neurophysiology at the National Institute for Medical Research, the Francis Crick Institute and University College London, all provide an excellent surrounding to successfully conduct this new study.