The anterior cerebral artery (ACA) supplies blood predominantly to the frontal lobe including the prefrontal cortex. Our laboratory reported that prefrontal oxygenated-hemoglobin concentration (Oxy-Hb) increases prior to and at exercise onset, as long as exercise is arbitrarily started. Moreover, the increased prefrontal oxygenation seems independent of both exercise intensity and muscle mass. If so, mean blood velocity of the ACA (ACA_BV) should increase with "very light motor effort", concomitantly with the pre-exercise and initial increase in prefrontal Oxy-Hb. This study aimed to examine the responses in ACA_BV and vascular conductance index (ACA_VCI) of the ACA as well as prefrontal Oxy-Hb during arbitrary or cued finger-tapping in 12 subjects, an activity with a Borg scale perceived exertion rating of 7 (median). With arbitrary start, ACA_BV increased at tapping onset (14 ± 9%) via an elevation in ACA_VCI. Likewise, prefrontal Oxy-Hb increased at the onset of tapping with a time course resembling that of ACA_BV. A positive cross-correlation between the initial changes in ACA_BV and prefrontal Oxy-Hb was found significant in 67% of subjects, having a time lag of 2 s, while a positive linear regression between them was significant in 75% of subjects. When tapping was forced to start by cue, the initial increases in ACA_BV, ACA_VCI, and prefrontal Oxy-Hb were delayed and blunted as compared to an arbitrary start. Thus active vasodilatation of the ACA vascular bed occurs at tapping onset, as long as tapping is arbitrarily started, and contributes to immediate increases in blood flow and prefrontal oxygenation.

中文翻译：

---

随意拍打开始时大脑前动脉血流速度和前额叶氧合与中枢指令相关的增加

大脑前动脉 (ACA) 主要向包括前额叶皮层在内的额叶供血。我们的实验室报告说，只要运动是任意开始的，前额叶氧合血红蛋白浓度 (Oxy-Hb) 在运动开始之前和开始时都会增加。此外，增加的前额叶氧合似乎与运动强度和肌肉质量无关。如果是这样，ACA 的平均血流速度 (ACA _BV ) 应该随着“非常轻微的运动努力”而增加，伴随着运动前和前额叶 Oxy-Hb 的初始增加。本研究旨在检查 ACA _BV和血管电导指数 (ACA _{VCI) 的反应}) 的 ACA 以及前额叶 Oxy-Hb 在 12 名受试者的任意或提示手指敲击期间，Borg 量表感知劳累等级为 7（中位数）的活动。在任意开始时，ACA _BV在攻丝开始时增加 (14 ± 9%) 通过 ACA _VCI的升高。同样，前额叶 Oxy-Hb 在敲击开始时增加，其时间过程与 ACA _BV相似。在 67% 的受试者中发现ACA _BV的初始变化与前额叶 Oxy-Hb 之间存在显着的正相关，时滞为 2 秒，而在 75% 的受试者中，它们之间的正线性回归显着。当提示被迫开始敲击时，ACA _BV、ACA _VCI的初始增加和前额叶 Oxy-Hb 与任意开始相比被延迟和钝化。因此，ACA 血管床的主动血管舒张发生在敲击开始时，只要随意开始敲击，并有助于立即增加血流量和前额叶氧合。