Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University School of Psychology, Maindy Road, Cardiff CF24 4HQ, UK.
Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University School of Psychology, Maindy Road, Cardiff CF24 4HQ, UK; Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University School of Medicine, University Hospital Wales, Heath Park, CF14 4XN, UK.
Neuroscience. 2019 Apr 1;403:54-69. doi: 10.1016/j.neuroscience.2018.03.018. Epub 2018 Mar 23.
The process of neurovascular coupling ensures that increases in neuronal activity are fed by increases in cerebral blood flow. Evidence suggests that neurovascular coupling may be impaired in Multiple Sclerosis (MS) due to a combination of brain hypoperfusion, altered cerebrovascular reactivity and oxygen metabolism, and altered levels of vasoactive compounds. Here, we tested the hypothesis that neurovascular coupling is impaired in MS. We characterized neurovascular coupling as the relationship between changes in neuronal oscillatory power within the gamma frequency band (30-80 Hz), as measured by magnetoencephalography (MEG), and associated hemodynamic changes (blood oxygenation level dependent, BOLD, and cerebral blood flow, CBF) as measured by functional MRI. We characterized these responses in the visual cortex in 13 MS patients and in 10 matched healthy controls using a reversing checkerboard stimulus at five visual contrasts. There were no significant group differences in visual acuity, P100 latencies, occipital gray matter (GM) volumes and baseline CBF. However, in the MS patients we found a significant reduction in peak gamma power, BOLD and CBF responses. There were no significant differences in neurovascular coupling between groups, in the visual cortex. Our results suggest that neuronal and vascular responses are altered in MS. Gamma power reduction could be an indicator of GM dysfunction, possibly mediated by GABAergic changes. Altered hemodynamic responses confirm previous reports of a vascular dysfunction in MS. Despite altered neuronal and vascular responses, neurovascular coupling appears to be preserved in MS, at least within the range of damage and disability studied here.
神经血管耦合过程确保神经元活动的增加得到脑血流的增加的支持。有证据表明，由于脑灌注不足、脑血管反应和氧代谢改变以及血管活性化合物水平改变的综合作用，神经血管耦合可能在多发性硬化症（MS）中受损。在这里，我们检验了神经血管耦合在 MS 中受损的假设。我们通过磁共振功能成像（fMRI）测量神经元在伽马频带（30-80 Hz）内的振荡功率变化（MEG），并将其与相关的血液动力学变化（血氧水平依赖，BOLD 和脑血流，CBF）相关联，从而描述了神经血管耦合。我们使用 5 种视觉对比度的反转棋盘刺激，在 13 名 MS 患者和 10 名匹配的健康对照者的视觉皮层中描述了这些反应。在视力、P100 潜伏期、枕叶灰质（GM）体积和基线 CBF 方面，两组之间没有显著的差异。然而，在 MS 患者中，我们发现峰值伽马功率、BOLD 和 CBF 反应明显减少。两组之间的神经血管耦合在视觉皮层中没有显著差异。我们的结果表明，神经元和血管反应在 MS 中发生改变。伽马功率降低可能是 GM 功能障碍的一个指标，可能由 GABA 能变化介导。血液动力学反应的改变证实了以前报道的 MS 中的血管功能障碍。尽管神经元和血管反应发生改变，但神经血管耦合在 MS 中似乎得到了保留，至少在我们研究的损伤和残疾范围内是如此。
