Dynamic cerebral autoregulation during cognitive task: Effect of hypoxia.
Dynamic cerebral autoregulation during cognitive task: Effect of hypoxia.
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认知任务期间的动态大脑自动调节：缺氧的影响。
DOI：
10.1152/japplphysiol.00909.2017
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发表时间：
2018
期刊：
影响因子：
3.3
通讯作者：
Shibasaki M.
中科院分区：
文献类型：
--
作者：
Ogoh S;Nakata H;Miyamoto T;Bailey DM;Shibasaki M.
氧分压和二氧化碳分压改变后脑血流量（CBF）的变化可以改变动态脑自动调节（CA）。虽然认知活动会增加 CBF，但它对 CA 的影响程度仍有待确定。在本研究中，我们确定了认知任务期间动态 CA 是否会减少，以及缺氧是否会进一步加剧损害。 14名年轻健康受试者在常氧和缺氧期间（吸入O2分数 = 12%）执行简单的Go/No-go任务，并检查平均动脉压（MAP）和平均大脑中动脉血流速度（MCAVmean）之间的对应关系。通过传递函数分析评估与动脉压变化相关的动态 CA 和 MCAV 稳态变化。虽然 MCAV 平均值在认知活动期间增加（P < 0.001），但缺氧并没有引起任何额外的变化（与常氧相比，P = 0.804）。认知表现也不受缺氧影响（反应时间，P= 0.712；误差，P= 0.653）。在认知活动期间观察到极低频和低频相移（VLF 和 LF；P= 0.021 和 P= 0.01）的减少和 LF 增益的增加（P= 0.037），这意味着动态 CA 受损。虽然缺氧也增加了 VLF 增益 (P< 0.001)，但它未能导致动态 CA 发生任何额外的改变。总的来说，我们的研究结果表明，认知活动期间动态 CA 受到损害，与全身 O2 可用性改变无关，尽管我们承认与额外的竞争性输入（尽管未定义）相关的解释性并发症，可能会扭曲 MAP-MCAV 平均关系。新的和值得注意的在常氧期间，认知活动在增加脑灌注时被证明会减弱动态脑自动调节 (CA)，但无法改变反应时间，从而质疑其功能意义。缺氧期间没有观察到进一步的变化，这表明动态 CA 受损的发生与全身 O2 可用性的改变无关。然而，鉴于额外输入的混杂影响可能会扭曲平均动脉压-平均大脑中动脉血流速度关系，受损的动态 CA 可能反映了技术假象。
Changes in cerebral blood flow (CBF) subsequent to alterations in the partial pressures of oxygen and carbon dioxide can modify dynamic cerebral autoregulation (CA). While cognitive activity increases CBF, the extent to which it impacts CA remains to be established. In the present study we determined whether dynamic CA would decrease during a cognitive task and whether hypoxia would further compound impairment. Fourteen young healthy subjects performed a simple Go/No-go task during normoxia and hypoxia (inspired O2fraction = 12%), and the corresponding relationship between mean arterial pressure (MAP) and mean middle cerebral artery blood velocity (MCAVmean) was examined. Dynamic CA and steady-state changes in MCAVin relation to changes in arterial pressure were evaluated with transfer function analysis. While MCAVmeanincreased during the cognitive activity (P< 0.001), hypoxia did not cause any additional changes (P= 0.804 vs. normoxia). Cognitive performance was also unaffected by hypoxia (reaction time,P= 0.712; error,P= 0.653). A decrease in the very low- and low-frequency phase shift (VLF and LF;P= 0.021 andP= 0.01) and an increase in LF gain were observed (P= 0.037) during cognitive activity, implying impaired dynamic CA. While hypoxia also increased VLF gain (P< 0.001), it failed to cause any additional modifications in dynamic CA. Collectively, our findings suggest that dynamic CA is impaired during cognitive activity independent of altered systemic O2availability, although we acknowledge the interpretive complications associated with additional competing, albeit undefined, inputs that could potentially distort the MAP-MCAVmeanrelationship.NEW & NOTEWORTHYDuring normoxia, cognitive activity while increasing cerebral perfusion was shown to attenuate dynamic cerebral autoregulation (CA) yet failed to alter reaction time, thereby questioning its functional significance. No further changes were observed during hypoxia, suggesting that impaired dynamic CA occurs independently of altered systemic O2availability. However, impaired dynamic CA may reflect a technical artifact, given the confounding influence of additional inputs that could potentially distort the mean arterial pressure-mean middle cerebral artery blood velocity relationship.