81198
document
Effect of perception of mechanical loading on human respiratory pattern regulation . We applied external flow resistive ( R ) and elastic ( E ) mechanical loads over the entire respiratory cycle to five normal subjects by using a pseudorandom loading protocol . Loads ranged in magnitude from imperceptible ( R0/E0 ) through just perceptible ( R1/E1 ) to large ( R2/E2 ) and resulted in respiratory pattern responses that were due to reflex responses alone ( R0/E0 ) or to a combination of reflex responses and behavioral reactions to the perception of impeded breathing ( R1/E1 and R2/E2 ) . Pattern regulation dynamics were estimated from the computed impulse responses of tidal volume and inspiratory and expiratory durations . We anticipated that emergence of behavioral contributions would be marked by increased variability in response strategies and by increased nonlinearity in the observed responses . Regarding the immediate pattern response to loading , there was a tendency for increased qualitative variation across subjects as the load size increased , but the within-subject variability ( coefficient of variation ) was unaffected . We found no evidence for increased nonlinearity as loads became perceptible . The emergence of behavioral control in some instances seemed to be marked by reduction of complexity of the impulse response to one dominated by the zeroth-order lag , leading to dynamically simpler responses compared to control .
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Intervention_Physical
external flow resistive ( R ) and elastic ( E ) mechanical loads
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Intervention_Educational
imperceptible
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Intervention_Educational
just perceptible
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Intervention_Educational
large
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Outcome_Physical
human respiratory pattern
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Outcome_Physical
Pattern regulation dynamics
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Outcome_Physical
the computed impulse responses of tidal volume and inspiratory and expiratory durations
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Outcome_Physical
variability in response strategies
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Outcome_Physical
nonlinearity
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Outcome_Physical
qualitative variation
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Participant_Sample-size
five
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Participant_Condition
normal