Morpho-functional properties of interneurons born at different developmental stages in the adult olfactory bulb

嗅觉系统是最古老的感觉方式之一，对许多动物物种的生存至关重要。嗅觉提供食物位置的重要信息，并影响社会和性行为。在哺乳动物中，气味是由嗅觉上皮内的嗅觉感觉神经元感知的。感觉信息随后被转移到嗅球，在嗅球主细胞和中间神经元对其进行处理。在嗅球中，中间神经元的数量以100:1的比例大大超过主细胞，并且在动物的整个生命周期中，嗅球保持着更新其神经元数量的能力。新神经元以及出生后早期的细胞的形态功能特性仍然难以捉摸。此外，目前尚不清楚这些细胞如何对感觉刺激作出反应，以及它们在对气味刺激作出反应时的功能和结构改变。最后，主要细胞在不同发育阶段出生的细胞的成熟和整合中的作用仍然完全不清楚。******我们提出了一系列旨在研究不同发育时期出生的神经元在嗅球中的功能作用的实验。通过形态学和电生理记录，结合光遗传刺激，我们将验证成年期出生的神经元带来的神经回路特性是先前存在的中间神经元无法实现的假设。此外，我们将使用气味刺激后的体内固有光信号（IOS）成像，成年和早期出生的中间神经元的结构和功能特性的双光子延时成像的强大组合，以了解这些细胞在球回路中的意义。总的来说，这些实验将使我们能够理解成人大脑为什么以及如何产生新的神经元，并将其整合到已经存在的嗅球功能回路中。*****

The olfactory system is one of the oldest sensory modalities and is essential for the survival of many animal species. Olfaction provides vital information about food location and influences social and sexual behaviors. In mammals, the odors are perceived by the olfactory sensory neurons contained within olfactory epithelium. The sensory information is then transferred into the olfactory bulb where it is processed by the bulbar principal cells and interneurons. In the olfactory bulb the population of interneurons largely outnumbers the principal cells by the ratio 100:1 and remarkably, olfactory bulb retains a capacity to renew its neuronal population throughout the life span of animal. The morpho-functional properties of new neurons as well as cells born during early postnatal life remain still elusive. In addition, it is not clear how these cells respond to sensory stimulation and what are their functional and structural modifications in response to odor stimulation. Finally, the role of principall cells in the maturation and integration of cells born at different developmental stages remains completely unclear. ******We propose the series of experiments aiming at investigation of functional role of neurons born at different developmental periods in the olfactory bulb. By using morphological and electrophysiological recordings, combined with optogenetic stimulation we will test the hypothesis that neurons born in the adulthood bring to the neuronal circuitry properties that cannot be fulfilled by pre-existing population of interneurons. In addition, we will use powerful combination of in vivo intrinsic optical signal (IOS) imaging following odor stimulation, two-photon time-lapse imaging of structural and functional properties of adult-born and early-born interneurons to understand the implications of these cells in the bulbar circuitry. Overall these experiments will allow us to understand why and how the adult brain produces and incorporates new neurons into already existing, functioning circuits of the olfactory bulb.*****