Regulation of Respiration: “The Black Box”

Abstract

A close relation between the state of wakefulness, the EEG and respiration was previously demonstrated. It was assumed that as opening and closing of the eyes influence the EEG and probably the state of wakefulness, the responsiveness of the respiratory center may likewise be influenced by the single act of closing the eyes. Seven subjects were studied in the steady state of rest, breathing ambient air, 4-5% CO2 in air, or 11% O2 in N2. In experimental periods of 4-5 min their pulmonary ventilation and alveolar PCO2 [CO2 tension] were measured while they randomly were either reading a book, or were blindfolded. In all 3 conditions, closing of the eyes resulted in a mean decrease of .ovrhdot.VE [ventilation] of 8 to 14% with a concomitant increase of PACO2 [alveolar PCO2] of about 1 mmHg. It is tentatively suggested that other and stronger central or peripheral stimuli impinging on the reticular formation of the brain may explain the changed sensitivity of the respiratory center towards the chemical stimuli in conditions like exercise, chronic hypoxia, etc.