Understanding the neurobiology of complex behaviors requires measurement of activity in the discrete population of active neurons, neuronal ensembles, which control the behavior. Conventional neuroimaging techniques ineffectively measure neuronal ensemble activity in the brain because they assess the average regional neuronal activity instead of the specific activity of the neuronal ensemble that mediates the behavior. Our functional molecular photoacoustic tomography (FM-PAT) system allows direct imaging of Fos-dependent neuronal ensemble activation in Fos-LacZ transgenic rats in vivo. We tested four experimental conditions and found increased FM-PAT signal in prefrontal cortical areas in rats undergoing conditioned fear or novel context exposure. A parallel immunofluorescence ex vivo study of Fos expression found similar findings. These findings demonstrate the ability of FM-PAT to measure Fos-expressing neuronal ensembles directly and support a mechanistic role for the prefrontal cortex in higher-order processing of response to specific stimuli or environmental cues.

中文翻译：

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Fos-LacZ 转基因大鼠条件性恐惧学习后前额皮质神经元群的体内光声成像定量

了解复杂行为的神经生物学需要测量控制行为的离散活跃神经元群（神经元群）的活动。传统的神经成像技术无法有效地测量大脑中的神经元整体活动，因为它们评估的是平均区域神经元活动，而不是介导行为的神经元整体的特定活动。我们的功能性分子光声断层扫描 (FM-PAT) 系统可以对 Fos-LacZ 转基因大鼠体内的 Fos 依赖性神经元群激活进行直接成像。我们测试了四种实验条件，发现经历条件性恐惧或新环境暴露的大鼠前额皮质区域的 FM-PAT 信号增加。 Fos 表达的平行免疫荧光离体研究也发现了类似的结果。这些发现证明了 FM-PAT 能够直接测量表达 Fos 的神经元群，并支持前额叶皮层在对特定刺激或环境线索的反应的高阶处理中的机械作用。