How the involuntary (bulbospinal) and voluntary (corticospinal) pathways interact in respiratory muscle control is not established. To determine the role of excitatory corticobulbar pathways in humans, studies typically compare electromyographic activity (EMG) or evoked responses in respiratory muscles during hypercapnic and voluntary tasks. Although ventilation is matched between tasks by having participants track signals of ventilation, these tasks may not result in matched respiratory muscle activity. The aim of this study was to describe respiratory muscle activity and ribcage and abdominal excursions during two different voluntary conditions, compared to hypercapnic hyperventilation. Ventilation was matched in the voluntary conditions via (i) a simple target of lung volume ('volume tracking') or (ii) targets of both ribcage and abdominal excursions, adjusted to end-expiratory lung volume in hypercapnic hyperventilation ('bands tracking'). Compared to hypercapnic hyperventilation, respiratory parameters such as tidal volume were similar, but the ratio of ribcage to abdominal excursion was higher for both voluntary tasks. Inspiratory scalene and parasternal intercostal muscle activity was higher in volume tracking, but diaphragm and abdominal muscle activity showed little to no change. There were no differences in muscle activity in bands tracking for any muscle, compared to hypercapnic hyperventilation. An elevated ratio of ribcage to abdominal excursion in the bands tracking task indicates that participants could not accurately match the targets in this condition. Inspiratory muscle activity is altered in some muscles in some voluntary tasks, compared to hypercapnia. Therefore, differences in muscle activity should be considered in interpretation of studies that use these protocols to investigate respiratory muscle control.

中文翻译：

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自愿性呼吸追踪任务中的呼吸肌活动：对呼吸运动控制的评估意义。

尚未确定非自愿（球鼻）和自愿（皮质脊髓）途径如何在呼吸肌控制中相互作用。为了确定兴奋性皮层球通路在人类中的作用，研究通常会比较高碳酸血症和自愿性任务期间呼吸肌的肌电图活动（EMG）或诱发反应。尽管通过让参与者跟踪通气信号来使任务之间的通气匹配，但是这些任务可能不会导致匹配的呼吸肌活动。这项研究的目的是描述与高碳酸血症性过度换气相比在两种不同的自愿条件下的呼吸肌活动，胸腔和腹部运动。通过以下方式在自愿条件下进行通气匹配：（i）一个简单的肺容量目标（“容量跟踪” ）或（ii）调整为高碳酸血症性过度换气时的呼气末肺体积（“条带追踪”）的胸腔和腹部偏移的目标。与高碳酸血症通气相比，诸如潮气量之类的呼吸参数相似，但两项自愿性任务的胸腔与腹部偏移之比均较高。在体积追踪中，吸气性斜角肌和胸骨旁肋间肌活动较高，但diaphragm肌和腹肌活动几乎没有变化。与高碳酸血症性过度换气相比，在追踪任何肌肉的乐队中，肌肉活动没有差异。在乐队跟踪任务中，胸腔与腹部偏移的比率升高表明在这种情况下参与者无法准确匹配目标。与高碳酸血症相比，某些自愿性任务中某些肌肉的吸气肌肉活动发生了变化。因此，在解释使用这些方案研究呼吸肌控制的研究时，应考虑肌肉活动的差异。