The effects of acute stress on interoceptive learning and somatic complaints in a differential respiratory conditioning paradigm

Background: Acute stress during the consolidation phase enhances declarative memory. It is so far unknown whether classical conditioning (CC) of interoceptive signals is also facilitated by stress. This question is relevant as CC plays a role in altered interoception, which might be an important mechanism for symptom generation in stress-related disorders. Thus, the aim of the study was to test if CC can be facilitated by post-learning stress effects.
Methods: Fifty-five healthy students were tested. We used a differential conditioning paradigm, employing odors and low intensity breathing loads. Two odors served as conditioned stimuli (CS), while breathing loads were used as unconditioned stimuli (US). One odor was simultaneously presented with the occlusions (CS+), the other was presented when the participants breathed normally (CS-). The CC session was followed by a socially-evaluated cold pressor stress test (SECPT) or a control task. Breathing frequency (BF) and somatic complaints (SC) were assessed after each trial as unconditioned responses (UR).
Results: We expected a CS-US contingency learning in CS+ the condition only, which would be stronger when combined with stress. However, no significant conditioning effects, i.e. no significant differences - in SC ratings or BF between CS+ and CS- condition were found. Furthermore, no stress effects were observed.
Discussion: Our findings have implications for the psychobiological and learning processes behind stress related disorders, as they may not be primarily related to CC of interoceptive sensations. This knowledge may inform future treatment approaches.