Guthrie K M, Gall C M
Department of Anatomy and Neurobiology, University of California, Irvine 92717, USA.
Chem Senses. 1995 Apr;20(2):271-82. doi: 10.1093/chemse/20.2.271.
Induction of immediate-early gene expression, in particular c-fos, can be used to map neural activity in many brain areas, including the olfactory system. By making use of the resolution provided by cellular localization of c-fos mRNA or Fos protein, those neurons activated by a particular odor stimulus can be identified. Odor presentation to awake rats increases c-fos expression by bulb neurons located in discrete portions of the glomerular layer and in the underlying mitral and granule cell layers. The translaminar distribution of co-ordinately activated cells corresponds to the 'functional unit' predicted by the synaptic organization of the bulb, and the distribution of these units throughout the bulb as a whole differs for different odors. The bulbar pattern of activity is spatially altered by changes in odor intensity and during the course of postnatal development. These findings support the idea that distributed patterns of odor-induced neuronal activity contribute to the encoding of olfactory information. Moreover, the role of c-fos in the transcriptional regulation of other genes suggests a mechanism whereby odor experience can lead to long-term changes in the olfactory system.
立即早期基因表达的诱导，特别是c-fos的诱导，可用于绘制包括嗅觉系统在内的许多脑区的神经活动图谱。通过利用c-fos mRNA或Fos蛋白细胞定位所提供的分辨率，可以识别由特定气味刺激激活的那些神经元。向清醒大鼠呈现气味会增加位于肾小球层离散部分以及下方的二尖瓣和颗粒细胞层中的球茎神经元的c-fos表达。协同激活细胞的跨层分布对应于由球茎的突触组织预测的“功能单元”，并且这些单元在整个球茎中的分布因不同气味而异。气味强度的变化以及在出生后发育过程中，球茎的活动模式在空间上会发生改变。这些发现支持了这样一种观点，即气味诱导的神经元活动的分布式模式有助于嗅觉信息的编码。此外，c-fos在其他基因转录调控中的作用提示了一种机制，通过该机制气味体验可导致嗅觉系统的长期变化。
