Emotional stimuli can cause airway constriction; however, it is uncertain whether a dimensional or categorical model of emotion can better describe airway changes. Also, little is known about the affective modulation of respiration and vagal activity, which can influence airway tone. We studied changes in oscillatory resistance (Ros), respiration, and respiratory sinus arrhythmia (RSA) in asthmatics and controls during viewing of affective pictures eliciting anxiety, depression, disgust, happiness, contentment, erotic tension, or neutral affect. Ros, respiration, cardiac activity, and self-report were measured during picture presentations. Ros increased monotonically with picture unpleasantness mainly due to disgust pictures. RSA and respiratory timing parameters were particularly sensitive to erotic pictures. Differences between asthmatics and controls were minimal, suggesting that airway responses to unpleasant pictures are not specific to asthma.

We studied the modulation of oscillatory resistance (R(os)) by viewing and imagery of affective pictures. Thirty nonasthmatic participants viewed 36 affective slides precategorized as positive, neutral, and negative in valence. Each picture was presented for 15 s, followed by an imagery epoch of 15 s. R(os), facial EMGs, respiration, skin conductance response, heart period, and respiratory sinus arrhythmia were measured throughout the session, as well as viewing time and ratings of pleasure, arousal, and interest. Increases of R(os) were observed for negative pictures, and little changes for positive or neutral pictures. Other physiological parameters did not mirror this response pattern, leaving no clear indication for a ventilatory or vagal origin of R(os) changes. Overall differences between behavioral contexts of visual processing and imagery revealed evidence for a coupling of cardiac and respiratory responses, which included changes in R(os). The findings in R(os) are discussed in the light of earlier discrepant findings on the affective modulation of airway resistance and cardiac activity.

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We tested the assumption that the slope of the within-individual regression equation of respiratory sinus arrhythmia (RSA) normalized by tidal volume (V(T)) upon respiratory cycle length (T(TOT)) can characterize ventilatory RSA modulation independent of cardiac vagal tone, whereas the intercept is varying as a function of vagal tone. We also explored whether a variation of V(T) is necessary to estimate slopes reliably. Four 3-min sequences paced at 8-18 cycles/min were performed supine and standing. Participants also breathed the same sequences in supine posture with voluntarily varying V(T). The mean slope of RSA/V(T) upon T(TOT) was identical, and the mean intercept was lower for standing than supine (spontaneous V(T)) conditions. Stability of slopes was low between body postures, and was higher between spontaneous V(T) versus varying V(T) at the same body posture. The regression of RSA/V(T) upon T(TOT) allows for a valid estimation of ventilatory influences on RSA.

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