The Functional Organization of Inhibition in the Olfactory Bulb In Vivo

描述（由申请人提供）：在嗅球中，一个单一的突触将传入的感觉输入和投射到高级皮质区域的主要神经元分开。然而，这个结构中的绝大多数细胞和连接都致力于两个不同的抑制回路：一个位于肾小球层的表面，另一个涉及肾小球内层的颗粒细胞。在它们最初被描述后不久，就有人提出了这个建议

DESCRIPTION (provided by applicant): In the olfactory bulb, a single synapse separates afferent sensory input and the principal neurons that project to higher cortical areas. Nevertheless, the vast majority of cells and connections in this structure are devoted to two distinct inhibitory circuits: one located superficially in the glomerular layer and one involving granule cells in infraglomerular layers. Soon after they were initially described, it was suggested that these inhibitory circuits might provide center-surround inhibition in an analogous fashion to other primary sensory areas. Nevertheless, the manner in which these circuits are activated by olfactory stimuli in vivo has yet to be demonstrated, and their importance in shaping olfactory bulb output remains controversial. In this proposal, the spread of inhibition laterally from the sites of olfactory receptor neuron input through the glomerular layer will be directly visualized t determine how lateral inhibition at this level might contribute to olfactory information processing In addition, the postsynaptic effect of inhibition arising from both lateral circuits will be assesed in identified olfactory bulb output neurons. These experiments will provide crucial insights into the role of lateral inhibitory circuits in vivo, and, by determining the differential effects of thse circuits on the excitability of different classes of output neurons, a better understanding of parallel pathways projecting to higher brain structures.