Does cerebrovascular disease affect the coupling between neuronal activity and local haemodynamics?
Does cerebrovascular disease affect the coupling between neuronal activity and local haemodynamics?
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DOI：
10.1093/brain/awh012
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发表时间：
2004-01-01
期刊：
影响因子：
14.5
通讯作者：
Tecchio, F
中科院分区：
文献类型：
--
作者：
Rossini, PM;Altamura, C;Tecchio, F
通过比较脑磁图(脑磁图)和血氧水平依赖的功能磁共振成像(BOLD FMRI)对正中神经电刺激的反应，探讨严重脑血管缺陷患者的神经生理和脑血管代谢表现之间的关系。尽管使用了相同的刺激，这两种技术在对照组(10名受试者)中引起了总是可检测到的反应，但在我们的患者样本(10名受试者)中显示出不相关的激活特性。所有患者在患侧和非患侧大脑半球都显示出清晰的脑磁图信号，这表明初级感觉运动皮质神经元的放电很好地同步，刺激锁定，但一些患者在患侧或非患侧大脑半球没有显示出fMRI激活。为了阐明这种脱钩的原因，我们调查了病变部位、白质高信号、当前用药、危险因素、颈部血管解剖和经颅多普勒(TCD)测量的脑血管运动反应性(VMR)在二氧化碳吸入过程中的可能作用。除了血管运动反应性改变外，神经元的激活特性和所考虑的任何因素都与fMRI缺乏激活无关，相反，血管运动反应性的改变与此密切相关。在唯一受微血管病变影响的患者中，保留的VMR与双侧缺失的BOLD配对。这一发现表明，大胆的对比剂可能比TCD对慢性微血管损伤更敏感，衡量的是小血管而不是大血管的反应性。
The relationship between neurophysiological and cerebrovascular-metabolic findings in patients affected by severe cerebrovascular deficits was investigated by comparing magnetoencephalographic (MEG-evoked fields) and blood oxygen level-dependent functional MRI (BOLD fMRI) responses to median nerve electric stimulation. Despite the use of identical stimuli, the two techniques elicited always-detectable responses in the control group (10 subjects), but demonstrated uncorrelated activation properties in our patient sample (10 subjects). All patients showed clear MEG signals in both the affected and unaffected hemispheres, indicating well synchronized, stimulus-locked firing of neurons in the primary sensorimotor cortex, but some patients showed no fMRI activation in either the affected or the unaffected hemisphere. In order to clarify the origin of this uncoupling, we investigated the possible role of lesion site, white matter hyperintensities, current medication, risk factors, anatomy of the neck vessels, and cerebral vasomotor reactivity (VMR) as measured by transcranial Doppler (TCD) during CO2 inhalation. Neither neuronal activation properties nor any of the considered factors were related to the lack of fMRI activation, with the exception of altered vasomotor reactivity, which was, on the contrary, strongly related. Preserved VMR was paired with absent BOLD bilaterally in the only patient affected by microangiopathy. This finding suggests that BOLD contrast could be more sensitive than TCD to chronic microvascular impairments, measuring small- rather than large- vessel reactivity.