Suppressed neuronal activity and concurrent arteriolar vasoconstriction may explain negative blood oxygenation level-dependent signal
Suppressed neuronal activity and concurrent arteriolar vasoconstriction may explain negative blood oxygenation level-dependent signal
复制标题
DOI：
10.1523/jneurosci.0134-07.2007
复制
发表时间：
2007-04-18
影响因子：
5.3
通讯作者：
Dale, Anders M.
中科院分区：
文献类型：
--
作者：
Devor, Anna;Tian, Peifang;Dale, Anders M.
突触传递启动了一系列信号转导事件，这些事件将神经元活动与血流和氧合的局部变化相耦合。虽然一些血管活性分子和特定的细胞类型已经牵连，刺激诱导的神经元回路激活的血流动力学变化的转换仍然不清楚。我们使用躯体感觉刺激和一套在体成像工具来研究大鼠初级躯体感觉皮层的神经血管耦合。我们的刺激引起了净超极化包围的净神经元去极化的中心区域。血流动力学测量显示，主要去极化对应于氧合增加，而主要超极化对应于氧合减少。在单个表面小动脉的微观水平上，反应由扩张和收缩相的组合组成。重要的是，血管收缩的相对强度与氧合减少和神经元超极化的相对强度共变。这些结果表明，神经元抑制和同时发生的小动脉血管收缩对应于血氧含量的降低，这与负血氧水平依赖性功能磁共振成像信号一致。
Synaptic transmission initiates a cascade of signal transduction events that couple neuronal activity to local changes in blood flow and oxygenation. Although a number of vasoactive molecules and specific cell types have been implicated, the transformation of stimulus-induced activation of neuronal circuits to hemodynamic changes is still unclear. We use somatosensory stimulation and a suite of in vivo imaging tools to study neurovascular coupling in rat primary somatosensory cortex. Our stimulus evoked a central region of net neuronal depolarization surrounded by net hyperpolarization. Hemodynamic measurements revealed that predominant depolarization corresponded to an increase in oxygenation, whereas predominant hyperpolarization corresponded to a decrease in oxygenation. On the microscopic level of single surface arterioles, the response was composed of a combination of dilatory and constrictive phases. Critically, the relative strength of vasoconstriction covaried with the relative strength of oxygenation decrease and neuronal hyperpolarization. These results suggest that a neuronal inhibition and concurrent arteriolar vasoconstriction correspond to a decrease in blood oxygenation, which would be consistent with a negative blood oxygenation level-dependent functional magnetic resonance imaging signal.