Data from: Discharge patterning in rat olfactory bulb mitral cells in vivo

Here we present a detailed statistical analysis of the discharge characteristics of mitral cells of the main olfactory bulb of urethane-anesthetized rats. Neurons were recorded from the mitral cell layer, and antidromically identified by stimuli applied to the lateral olfactory tract. All mitral cells displayed repeated, prolonged bursts of action potentials typically lasting &gt;100s and separated by similarly long intervals; about half were completely silent between bursts. No such bursting was observed in non-mitral cells recorded in close proximity to mitral cells. Bursts were asynchronous amongst even adjacent mitral cells. The intraburst activity of most mitral cells showed strong entrainment to the spontaneous respiratory rhythm; similar entrainment was seen in some, but not all non-mitral cells. All mitral cells displayed a peak of excitability at ~25 ms after spikes, as reflected by a peak in the interspike interval distribution and in the corresponding hazard function. About half also showed a peak at about 6 ms, reflecting the common occurrence of doublet spikes. Non-mitral cells showed no such doublet spikes. Bursts typically increased in intensity over the first 20-30 s of a burst, during which time doublets were rare or absent. After 20-30s (in cells that exhibited doublets) doublets occurred frequently for as long as the burst persisted, in trains of up to 10 doublets. The last doublet was followed by an extended relative refractory period the duration of which was independent of train length. In cells that were excited by application of a particular odor, responsiveness was apparently greater during silent periods between bursts than during bursts. Conversely in cells that were inhibited by a particular odor, responsiveness was only apparent when cells were active. Extensive raw (event timing) data from the cells, together with details of those analyses, are provided as supplementary material, freely available for secondary use by others. <br>

本研究针对氨基甲酸乙酯麻醉（urethane-anesthetized）大鼠主嗅球（main olfactory bulb）僧帽细胞（mitral cells）的放电特性开展了详细的统计分析。实验从僧帽细胞层记录神经元，并通过施加于外侧嗅束（lateral olfactory tract）的刺激对其进行逆向识别。所有僧帽细胞均表现出重复出现的长时程动作电位爆发（bursts of action potentials），单次爆发通常持续时长超过100秒，且爆发间间隔时长相近；其中约半数细胞在爆发间期完全处于静息状态。在紧邻僧帽细胞区域记录到的非僧帽细胞（non-mitral cells）中，未观察到此类爆发活动。即便相邻的僧帽细胞，其爆发活动也完全异步。多数僧帽细胞的爆发内活动可强烈锁相于自发呼吸节律（spontaneous respiratory rhythm）；部分（而非全部）非僧帽细胞也表现出类似的节律同步现象。所有僧帽细胞均在锋电位出现后约25毫秒处出现兴奋性峰值，这一点可从峰间期分布（interspike interval distribution）及对应的危险函数（hazard function）的峰值得到印证。约半数僧帽细胞还在约6毫秒处出现另一峰值，这反映了双峰锋电位（doublet spikes）的常见发生情况。非僧帽细胞则未出现此类双峰锋电位。爆发强度通常在爆发开始后的前20~30秒内逐渐增强，此阶段双峰锋电位罕见或缺如。在出现双峰锋电位的细胞中，20~30秒后，双峰锋电位会在爆发持续期间频繁出现，形成最多包含10个双峰锋电位的序列。最后一个双峰锋电位出现后，会伴随一段延长的相对不应期（refractory period），其时长与双峰序列的长度无关。对于受到特定气味兴奋的细胞，其在爆发间静息期的响应强度明显高于爆发期间；反之，对于受到特定气味抑制的细胞，仅在细胞处于活动状态时才表现出明显的响应。本研究提供了各细胞的完整原始（事件时序）数据及相关分析细节，作为补充材料（supplementary material）公开共享，可供其他研究者二次使用。