Rinberg Dmitry, Koulakov Alex, Gelperin Alan
Monell Chemical Senses Center, Philadelphia, Pennsylvania, 19104, USA.
J Neurosci. 2006 Aug 23;26(34):8857-65. doi: 10.1523/JNEUROSCI.0884-06.2006.
Responses of mitral cells represent the results of the first stage of odor processing in the olfactory bulb. Most of our knowledge about mitral cell activity has been obtained from recordings in anesthetized animals. We compared odor-elicited changes in firing rate of mitral cells in awake behaving mice and in anesthetized mice. We show that odor-elicited changes in mitral cell firing rate were larger and more frequently observed in the anesthetized than in the awake condition. Only 27% of mitral cells that showed a response to odors in the anesthetized state were also odor responsive in the awake state. The amplitude of their response in the awake state was smaller, and some of the responses changed sign compared with their responses in the anesthetized state. The odor representation in the olfactory bulb is therefore sparser in awake behaving mice than in anesthetized preparations. A qualitative explanation of the mechanism responsible for this phenomenon is proposed.
二尖瓣细胞的反应代表了嗅球中气味处理第一阶段的结果。我们关于二尖瓣细胞活动的大部分知识都是通过对麻醉动物的记录获得的。我们比较了清醒行为小鼠和麻醉小鼠中气味引发的二尖瓣细胞放电率变化。我们发现，与清醒状态相比，麻醉状态下气味引发的二尖瓣细胞放电率变化更大，且更频繁地被观察到。在麻醉状态下对气味有反应的二尖瓣细胞中，只有27%在清醒状态下也对气味有反应。它们在清醒状态下的反应幅度较小，并且与麻醉状态下的反应相比，一些反应的符号发生了变化。因此，在清醒行为的小鼠中，嗅球中的气味表征比在麻醉制剂中更稀疏。本文提出了对这一现象背后机制的定性解释。
