Comparison of stimulus-evoked cerebral hemodynamics in the awake mouse and under a novel anesthetic regime.
Comparison of stimulus-evoked cerebral hemodynamics in the awake mouse and under a novel anesthetic regime.
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DOI：
10.1038/srep12621
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发表时间：
2015-07-28
影响因子：
4.6
通讯作者：
Berwick J
中科院分区：
文献类型：
--
作者：
Sharp PS;Shaw K;Boorman L;Harris S;Kennerley AJ;Azzouz M;Berwick J
神经活动紧跟着脑血流的局部变化，这一过程被称为神经血管耦合。这些血流动力学变化构成了功能性磁共振成像（fMRI）对比的基础，并被用作神经活动的关联。麻醉在动物功能磁共振成像和神经血管研究中被广泛应用，然而，麻醉剂对神经和血管生理的影响是众所周知的，尤其是在小鼠中。因此，我们研究了一种新型“模块化”麻醉的有效性，该麻醉将可注射麻醉剂（芬太尼-氟尼松/咪达唑仑）和挥发性麻醉剂（异氟醚）结合在小鼠身上。为了表征感觉诱发的皮层血流动力学反应，我们使用光学成像光谱绘制了响应机械须刺激的组织氧合和血容量变化的功能图。在对麻醉方案进行微调后，刺激在体感觉皮层中引发了巨大而强劲的血流动力学反应，其特征是动脉快速激活，总血红蛋白和含氧血红蛋白增加，脱氧血红蛋白减少。总的来说，麻醉状态下引起的血流动力学反应的幅度和速度与清醒状态相似，表明新的麻醉组合显著降低了麻醉的影响。我们的发现对神经血管研究和纵向功能磁共振成像研究具有广泛的意义，这些研究越来越需要使用基因工程小鼠。
Neural activity is closely followed by a localised change in cerebral blood flow, a process termed neurovascular coupling. These hemodynamic changes form the basis of contrast in functional magnetic resonance imaging (fMRI) and are used as a correlate for neural activity. Anesthesia is widely employed in animal fMRI and neurovascular studies, however anesthetics are known to profoundly affect neural and vascular physiology, particularly in mice. Therefore, we investigated the efficacy of a novel ‘modular’ anesthesia that combined injectable (fentanyl-fluanisone/midazolam) and volatile (isoflurane) anesthetics in mice. To characterize sensory-evoked cortical hemodynamic responses, we used optical imaging spectroscopy to produce functional maps of changes in tissue oxygenation and blood volume in response to mechanical whisker stimulation. Following fine-tuning of the anesthetic regime, stimulation elicited large and robust hemodynamic responses in the somatosensory cortex, characterized by fast arterial activation, increases in total and oxygenated hemoglobin, and decreases in deoxygenated hemoglobin. Overall, the magnitude and speed of evoked hemodynamic responses under anesthesia resembled those in the awake state, indicating that the novel anesthetic combination significantly minimizes the impact of anesthesia. Our findings have broad implications for both neurovascular research and longitudinal fMRI studies that increasingly require the use of genetically engineered mice.