Yu Yuguo, Migliore Michele, Hines Michael L, Shepherd Gordon M
Center for Computational Systems Biology, The State Key Laboratory of Medical Neurobiology and Institutes of Brain Science, Fudan University, School of Life Sciences, Shanghai, 200433, China, Department of Neurobiology, Yale University School of Medicine, New Haven, Connecticut 06520, and
Department of Neurobiology, Yale University School of Medicine, New Haven, Connecticut 06520, and Institute of Biophysics, National Research Council, 90146 Palermo, Italy.
J Neurosci. 2014 Oct 8;34(41):13701-13. doi: 10.1523/JNEUROSCI.1834-14.2014.
The precise mechanism by which synaptic excitation and inhibition interact with each other in odor coding through the unique dendrodendritic synaptic microcircuits present in olfactory bulb is unknown. Here a scaled-up model of the mitral-granule cell network in the rodent olfactory bulb is used to analyze dendrodendritic processing of experimentally determined odor patterns. We found that the interaction between excitation and inhibition is responsible for two fundamental computational mechanisms: (1) a balanced excitation/inhibition in strongly activated mitral cells, leading to a sparse representation of odorant input, and (2) an unbalanced excitation/inhibition (inhibition dominated) in surrounding weakly activated mitral cells, leading to lateral inhibition. These results suggest how both mechanisms can carry information about the input patterns, with optimal level of synaptic excitation and inhibition producing the highest level of sparseness and decorrelation in the network response. The results suggest how the learning process, through the emergent development of these mechanisms, can enhance odor representation of olfactory bulb.
在嗅球中，通过独特的树突 - 树突突触微电路，突触兴奋和抑制在气味编码过程中相互作用的确切机制尚不清楚。在这里，使用啮齿动物嗅球中二尖瓣 - 颗粒细胞网络的放大模型来分析实验确定的气味模式的树突 - 树突处理。我们发现，兴奋和抑制之间的相互作用负责两种基本的计算机制：（1）在强烈激活的二尖瓣细胞中实现兴奋/抑制平衡，导致气味剂输入的稀疏表示；（2）在周围弱激活的二尖瓣细胞中出现不平衡的兴奋/抑制（抑制占主导），导致侧向抑制。这些结果表明这两种机制如何能够携带有关输入模式的信息，其中突触兴奋和抑制的最佳水平在网络响应中产生最高水平的稀疏性和去相关性。结果还表明，通过这些机制的涌现发展，学习过程如何能够增强嗅球的气味表征。
