Purpose: The cough reflex is an automatic protective reflex, which can be modulated by conscious effort
or other forms of top-down control. In this experiment, we investigated whether information about
harmfulness of a cough-inducing substance would augment cough reflex sensitivity and associated urgeto-cough.
Methods: Healthy participants (N ¼ 39) were randomized to receive information that they were to inhale
a harmless substance (natural citric acid), or a potentially harmful substance (a potent agro-chemical
acid). Using dosimeter-controlled inhalations, the dose of citric acid eliciting at least three coughs (C3)
was determined. Next, participants received 4 blocks of randomized presentations of citric acid at the C3
dose, a sub-threshold dose of citric acid and saline control.
Results: C3 was reached for 27/39 participants, and C3 thresholds were not influenced by harmfulness
information. During repeated citric acid presentations, framing the cough-inducing substance as a
potentially harmful chemical resulted in a greater urge-to-cough compared to information framing it as
natural citric acid (p < .01). The experimental manipulation did not influence cough frequencies.
Conclusions: Our findings show that harmfulness information influences urge-to-cough, corroborating
the role of cortical mechanisms in modulating the urge-to-cough and suggesting that cognitive manipulations
may contribute to cough treatment.