INFLUENCE OF DRIVE AND TIMING MECHANISMS ON BREATHING PATTERN AND VENTILATION DURING MENTAL TASK-PERFORMANCE

Assessment of multiple respiratory measures may provide insight into h ow behavioral demands affect the breathing pattern. This is illustrate d by data from a study among 44 subjects, in which tidal volume, respi ration rate? minute ventilation and indices of central drive and timin g mechanisms were assessed via inductive plethysmography, in addition to end-tidal PCO2. After a baseline, three conditions of a memory comp arison task were presented. The first two conditions differed only wit h regard to the presence or absence of feedback of performance (NFB an d FB). In the third 'all-or-nothing' (AON) condition, subjects only re ceived a monetary bonus, if their performance exceeded that of the pre vious two conditions. Minute ventilation increased from baseline to al l task conditions, and from NFB and FB to AON. Respiration rate increa sed in all task conditions, but there were no differences between task conditions. Tidal volume decreased during NFB: but was equal to basel ine during FB and AON. Of the respiratory control indices, inspiratory how rate covaried much more closely with minute ventilation than duty cycle. The task performance induced a minor degree of hyperventilatio n. The discussion focusses on how behavioral demands affect respirator y control processes to produce alterations in breathing pattern and ve ntilation. (C) 1998 Elsevier Science B.V. All rights reserved.