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Correct
As subjects
became acutely hypercapnic, the sense of effort to maintain the
ventilation target diminished while the sensation of breathlessness
increased. Breathlessness and effort in this experimental model
were dissociated. These results suggest that reflex stimulation
of the ventilatory muscles via activation of respiratory neurons
in the brainstem does not produce the same "corollary discharge"
to the sensory cortex as does voluntary activation of the ventilatory
muscles via the cortex; hence, the two conditions are perceived
differently.
| Figure 9.1: The Mean Change in Effort and Breathlessness Rating
for Each Subject for Conditions A (PCO2 = 40) and B
(PCO2 = 50)
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| Official
Journal of the American Thoracic Society. Copyright
American Lung Association. Reprinted with permission. |
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