Activation-flow coupling during graded cerebral ischemia
Activation-flow coupling during graded cerebral ischemia
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DOI：
10.1016/j.brainres.2005.04.024
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发表时间：
2005-06-14
期刊：
影响因子：
2.9
通讯作者：
Greenberg, JH
中科院分区：
文献类型：
--
作者：
Burnett, MG;Detre, JA;Greenberg, JH
大多数功能性神经影像技术依靠激活流耦合（AFC）来检测区域脑功能的变化，但 AFC 反应也可能在缺血等病理生理条件下发生改变。为了确定进行性缺血和 AFC 反应之间的关系，使用大鼠压迫缺血模型产生脑血流量减少的分级水平，并测量对前爪刺激的脑血流动力学反应。通过用配备激光多普勒探头的 4 毫米直径圆柱体压缩完整硬脑膜，并结合同侧颈总动脉闭塞，在雄性 Sprague-Dawley 大鼠（n = 16）中诱导体感皮质的分级缺血水平。在 CBF 减少的每个水平上，进行前爪电刺激，并记录信号平均激光多普勒和诱发电位反应。在所有 CBF 减少水平（与基线相比减少 0-90%）中都存在可见的 AFC 反应，并且反应的时间特征似乎在很大程度上得到保留。然而，AFC 反应的幅度在轻度缺血水平（流量减少 10%）时开始下降，并随着 CBF 的进一步减少而逐渐下降。诱发反应的幅度似乎与 AFC 幅度一致降低，并且似乎对缺血同样敏感。 AFC 似乎是脑缺血的敏感标志物，当 CBF 减少至高于可接受的梗塞阈值时，AFC 反应就会发生变化。然而，当流量减少到缺血阈值以下时，AFC 反应也会保留。 (c) 2005 Elsevier B.V. 保留所有权利。
Most functional neuroimaging techniques rely on activation-flow coupling (AFC) to detect changes in regional brain function, but AFC responses may also be altered during pathophysiological conditions such as ischemia. To define the relationship between progressive ischemia and the AFC response, graded levels of cerebral blood flow reduction were produced using a rat compression ischemia model, and the cerebral hemodynamic response to forepaw stimulation was measured. Graded levels of cortical ischemia of the somatosensory cortex were induced in male Sprague-Dawley rats (n = 16) by compressing the intact dura with a 4-mm-diameter cylinder equipped with a laser-Doppler probe, combined with ipsilateral common carotid artery occlusion. At each level of CBF reduction, electric forepaw stimulation was conducted, and signal-averaged laser Doppler and evoked potential responses were recorded. A visible AFC response was present at all levels of CBF reduction (0-90% reduction from baseline), and the temporal characteristics of the response appeared largely preserved. However, the amplitude of the AFC response began to decline at levels of mild ischemia (10% flow reduction) and progressively decreased with further CBF reduction. The amplitude of the evoked response appeared to decrease in concert with the AFC amplitude and appeared to be equally sensitive to ischemia. AFC appears to be a sensitive marker for cerebral ischemia, and alterations in the AFC response occur at CBF reductions above the accepted thresholds for infarction. However, the AFC response is also preserved when flow is reduced below ischemic thresholds. (c) 2005 Elsevier B.V. All rights reserved.