Relating Synaptic Plasticity to Changes in Odor Representation and Perception

嗅觉系统提供了一个独特的强大的环境，在其中探索哺乳动物的感觉可塑性，因为在嗅觉系统中最早的中央处理发生在嗅球的肾小球，一个结构，是物理和光学访问在体内的动物模型，因为最近的进展，分子遗传技术已经产生了很好的实验工具，在这方面的研究。使用分子遗传学工具和体内光学成像技术相结合，我最近表明，嗅觉系统表现出快速反馈突触前抑制从嗅觉神经释放的递质。我假设，这个电路的快速可塑性提供了自适应增益控制的主要感官输入从鼻子，从而发挥了重要作用，在编码的气味浓度和气味强度的感知。此外，初步数据表明，这种抑制回路可能会随着时间的推移而改变，以适应嗅觉环境的变化。这些实验的第一个目的是检验这一假设，即初级感觉输入到嗅球的突触前调制有助于气味浓度的编码。这些实验的第二个目的是使用光学成像技术来测试的假设，即在感官环境的变化引起的可塑性在输入到嗅球的气味的代表。这些实验的最终目的是使用行为分析来测试这种可塑性如何影响气味质量和强度的感知。

The olfactory system provides a uniquely powerful environment in which to explore sensory plasticity in mammals, because the earliest central processing in the olfactory system takes place in the glomeruli of the olfactory bulb, a structure that is physically and optically accessible in vivo in animal models, and because recent advances in molecular genetic technology have produced excellent experimental tools for studies in this area. Using a combination of molecular genetic tools and in vivo optical imaging techniques, I have recently shown that the olfactory system exhibits rapid feedback presynaptic inhibition of transmitter release from the olfactory nerve. I hypothesize that the rapid plasticity of this circuit provides adaptive gain control for the primary sensory input from the nose, and thus plays a major role in the encoding of odorant concentration and the perception of odor intensity. Moreover, preliminary data suggest that this inhibitory circuitry may change over time to accommodate changes in the olfactory environment. The first aim of these experiments is to test the hypothesis that this presynaptic modulation of primary sensory input to the olfactory bulb contributes to the encoding of odor concentration. The second aim of these experiments is to use optical imaging techniques to test the hypothesis that changes in sensory environment induces plasticity in the representation of odors at the input to the olfactory bulb. The final aim of these experiments is to use behavioral assays to test how this plasticity affects the perception of odor quality and intensity.