The effects of unpredictability and negative affect on perception and neural gating in different interoceptive...

Breathlessness and pain frequently co-occur in chronic conditions, and their unpredictability is often reported to amplify perception and negative affect (NA), however any common neural mechanisms remain largely unexplored. This study examined the effects of (unpredictable) bodily threat on perception and neural gating of respiratory and somatosensory stimuli. Healthy adults (N = 51) experienced brief paired inspiratory occlusions and electrocutaneous stimuli, with their neural activity monitored via electroencephalography. Neural gating was measured as a ratio of the N1 response to the second relative to the first stimulus in a pair. In 4/6 blocks, threatening stimulation, in form of additional loaded breaths or electrocutaneous pulses, was presented predictably or unpredictably. Participants reported: perceived intensity and unpleasantness of all stimuli, fear, trait NA and intolerance of uncertainty (IU). Threatening stimulation increased perception, fear, and N1 amplitudes, without affecting neural gating. There was no group effect of unpredictability, though interactions were found with NA and IU. Cross-modal correlations revealed significant baseline relationships in neural gating and perception, though not in their modulation by threat. The present findings demonstrate that respiratory and somatosensory modalities relate in baseline perception and neural gating, and exhibit similar modulation effects by unpleasant stimulation. Further research is encouraged to elucidate the underlying mechanisms of these relationships, and the potential interactions with stimulus unpredictability.