实验性癫痫模型中单事件血流反应与发作间期放电之间线性耦合的研究。
Investigation of linear coupling between single-event blood flow responses and interictal discharges in a model of experimental epilepsy.
机构信息
Centre National de la Recherche Scientifique, Unité Mixte de Rechereche 6193, 13402 Marseille Cedex 20, France.
出版信息
J Neurophysiol. 2010 Jun;103(6):3139-52. doi: 10.1152/jn.01048.2009. Epub 2010 Mar 24.
A successful outcome of epilepsy neurosurgery relies on an accurate delineation of the epileptogenic region to be resected. Functional magnetic resonance imaging (fMRI) would allow doing this noninvasively at high spatial resolution. However, a clear, quantitative description of the relationship between hemodynamic changes and the underlying epileptiform neuronal activity is still missing, thereby preventing the systematic use of fMRI for routine epilepsy surgery planning. To this aim, we used a local epilepsy model to record simultaneously cerebral blood flow (CBF) with laser Doppler (LD) and local field potentials (LFP) in rat frontal cortex. CBF responses to individual interictal-like spikes were large and robust. Their amplitude correlated linearly with spike amplitude. Moreover, the CBF response added linearly in time over a large range of spiking rates. CBF responses could thus be predicted by a linear model of the kind currently used for the interpretation of fMRI data, but including also the spikes' amplitudes as additional information. Predicted and measured CBF responses matched accurately. For high spiking frequencies (above approximately 0.2 Hz), the responses saturated but could eventually recover, indicating the presence of multiple neurovascular coupling mechanisms, which might act at different spatiotemporal scales. Spatially, CBF responses peaked at the center of epileptic activity and displayed a spatial specificity at least as good as the millimeter. These results suggest that simultaneous electroencephalographic and blood flow-based fMRI recordings should be suitable for the noninvasive precise localization of hyperexcitable regions in epileptic patients candidate for neurosurgery.
癫痫神经外科的成功结果依赖于对要切除的致痫区的准确描绘。功能磁共振成像(fMRI)可以在高空间分辨率下进行非侵入性操作。然而,目前仍然缺乏对血流动力学变化与潜在癫痫样神经元活动之间关系的明确、定量描述,从而阻止了 fMRI 在常规癫痫手术规划中的系统应用。为此,我们使用局部癫痫模型在大鼠额叶皮层中同时记录激光多普勒(LD)和局部场电位(LFP)的脑血流(CBF)。单个癫痫样棘波的 CBF 反应大且稳定。其幅度与棘波幅度呈线性相关。此外,在很大的放电率范围内,CBF 反应随时间呈线性增加。因此,CBF 反应可以通过目前用于 fMRI 数据解释的线性模型进行预测,但也包括了作为附加信息的棘波幅度。预测和测量的 CBF 反应非常吻合。对于高放电频率(高于约 0.2 Hz),反应饱和,但最终可以恢复,表明存在多种神经血管耦合机制,它们可能在不同的时空尺度上起作用。空间上,CBF 反应在癫痫活动的中心达到峰值,并显示出至少与毫米一样好的空间特异性。这些结果表明,同步脑电图和基于血流的 fMRI 记录应该适用于对候选神经外科手术的癫痫患者的超兴奋性区域进行非侵入性精确定位。