Johnson Nathan E, Burma Joel S, Neill Matthew G, Burkart Joshua J, Fletcher Elizabeth Ks, Smirl Jonathan D
Cerebrovascular Concussion Lab, Faculty of Kinesiology, University of Calgary, Alberta, Canada.
Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.
J Cereb Blood Flow Metab. 2025 Feb 4:271678X251318922. doi: 10.1177/0271678X251318922.
This investigation explored the impact of partial pressure of end-tidal carbon dioxide (PCO) alterations on temporal neurovascular coupling (NVC) responses across the cardiac cycle and the influence of biological sex via a complex visual scene-search task (""). 10 females and 10 males completed five puzzles, each with 40 seconds of eyes open and 20 seconds of eyes closed, under PCO clamped at ∼40 mmHg (eucapnia), ∼55 mmHg (hypercapnia), and ∼25 mmHg (hypocapnia). Cerebral blood velocity (CBv) in the middle and posterior cerebral arteries (MCAv, PCAv) were measured via Transcranial Doppler ultrasound. Linear mixed-effects models with participants as a random effect analyzed NVC metrics, including baseline and peak CBv, relative increase, and area-under-the-curve (AUC30). During hypercapnic trials, reductions in PCAv and MCAv AUC30 were noted across the cardiac cycle (all ). Hypocapnic PCAv AUC30 was reduced (all ), as was systolic MCAv AUC30 (). Females displayed greater baseline PCA diastole (). No other biological sex differences were observed across conditions in baseline (all ), peak (all > ), relative increase (all ), and AUC30 metrics (all ). Despite differences in responses to hypercapnic and hypocapnic stimuli, NVC responses to complex visual tasks remain robust, across the physiological CO range.
本研究通过一项复杂的视觉场景搜索任务，探讨了呼气末二氧化碳分压（PCO）变化对整个心动周期中颞叶神经血管耦合（NVC）反应的影响以及生物性别的影响。10名女性和10名男性在PCO分别钳定于约40 mmHg（正常碳酸血症）、约55 mmHg（高碳酸血症）和约25 mmHg（低碳酸血症）的情况下，完成了五个拼图，每个拼图包括40秒睁眼和20秒闭眼。通过经颅多普勒超声测量大脑中动脉和大脑后动脉的脑血流速度（CBv，分别为MCAv和PCAv）。以参与者为随机效应的线性混合效应模型分析了NVC指标，包括基线和峰值CBv、相对增加量以及曲线下面积（AUC30）。在高碳酸血症试验期间，整个心动周期中均观察到PCAv和MCAv的AUC30降低（均为……）。低碳酸血症时PCAv的AUC30降低（均为……），收缩期MCAv的AUC30也降低（……）。女性在基线时大脑后动脉舒张期显示出更大的值（……）。在基线（均为……）、峰值（均为……＞……）、相对增加量（均为……）和AUC30指标（均为……）的所有条件下，未观察到其他生物性别差异。尽管对高碳酸血症和低碳酸血症刺激的反应存在差异，但在生理CO范围内，NVC对复杂视觉任务的反应仍然很强劲。
