Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, United Kingdom; Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Denmark.
Sci Rep. 2011;1:50. doi: 10.1038/srep00050. Epub 2011 Jul 29.
Although neurons are known to exhibit a broad array of intrinsic properties that impact critically on the computations they perform, very few studies have quantified such biophysical diversity and its functional consequences. Using in vivo and in vitro whole-cell recordings here we show that mitral cells are extremely heterogeneous in their expression of a rebound depolarization (sag) at hyperpolarized potentials that is mediated by a ZD7288-sensitive current with properties typical of hyperpolarization-activated cyclic nucleotide gated (HCN) channels. The variability in sag expression reflects a functionally diverse population of mitral cells. For example, those cells with large amplitude sag exhibit more membrane noise, a lower rheobase and fire action potentials more regularly than cells where sag is absent. Thus, cell-to-cell variability in sag potential amplitude reflects diversity in the integrative properties of mitral cells that ensures a broad dynamic range for odor representation across these principal neurons.
尽管已知神经元表现出广泛的内在特性，这些特性对它们执行的计算具有至关重要的影响，但很少有研究定量分析这种生物物理多样性及其功能后果。在这里，我们使用体内和体外全细胞记录显示，在超极化电位下，僧帽细胞的回弹去极化（凹陷）表达极为不均一，这种凹陷由 ZD7288 敏感电流介导，其特性与超极化激活环核苷酸门控（HCN）通道典型特征一致。凹陷表达的可变性反映了僧帽细胞功能多样化的群体。例如，与凹陷不存在的细胞相比，凹陷幅度大的细胞具有更高的膜噪声、更低的阈值和更规则地发射动作电位。因此，凹陷电位幅度的细胞间可变性反映了僧帽细胞整合特性的多样性，这确保了这些主要神经元对气味表示具有广泛的动态范围。
