Department of Biological Sciences and Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, PA 15213.
Proc Natl Acad Sci U S A. 2013 Oct 15;110(42):17083-8. doi: 10.1073/pnas.1303830110. Epub 2013 Sep 30.
Mitral/tufted (M/T) cells of the main olfactory bulb transmit odorant information to higher brain structures. The relative timing of action potentials across M/T cells has been proposed to encode this information and to be critical for the activation of downstream neurons. Using ensemble recordings from the mouse olfactory bulb in vivo, we measured how correlations between cells are shaped by stimulus (odor) identity, common respiratory drive, and other cells' activity. The shared respiration cycle is the largest source of correlated firing, but even after accounting for all observable factors a residual positive noise correlation was observed. Noise correlation was maximal on a ∼100-ms timescale and was seen only in cells separated by <200 µm. This correlation is explained primarily by common activity in groups of nearby cells. Thus, M/T-cell correlation principally reflects respiratory modulation and sparse, local network connectivity, with odor identity accounting for a minor component.
主嗅球的二尖瓣/发状细胞（M/T 细胞）将气味信息传递到大脑的更高结构。M/T 细胞之间动作电位的相对定时被提出用于编码此信息，并且对于下游神经元的激活是关键的。使用来自体内小鼠嗅球的整体记录，我们测量了细胞之间的相关性如何被刺激（气味）身份、共同呼吸驱动和其他细胞的活动所塑造。共享呼吸周期是相关发射的最大来源，但即使考虑到所有可观察的因素，仍观察到残余的正噪声相关性。噪声相关性在约 100 毫秒的时间尺度上达到最大值，并且仅在相隔<200 µm 的细胞中可见。这种相关性主要由附近细胞群的共同活动来解释。因此，M/T 细胞的相关性主要反映呼吸调制和稀疏的局部网络连接，而气味身份仅占次要成分。
