Cardiac signals and the interference of reward on attention and inhibitory control.

Interoceptive responses can modulate cognition and behavior; discrete cardiac signals can shape emotional and motivational adaptation towards reward-related cues, but also affect response inhibition. Novel addiction perspectives posit an interoceptive basis for the interplay between substance-related reward processing and inhibitory control, but there is a lack of behavioral evidence for this relationship. In this registered report, we investigated whether reward cues modulate cardiac-facilitated attention and motor inhibition. Fifty social drinkers completed an attentional visual search task and two instances of a stop signal task, in which alcohol or neutral stimuli were presented as targets or distractors. Stimuli were presented in synchrony with participants' cardiac phase (systole vs. diastole). This design allowed us to test whether cardiac signals amplify attentional biases in the presence of alcohol cues and influences inhibitory control. Overall, our results were predominantly null: alcohol cues did not produce significant attentional interference in any task, limiting conclusions about interoceptive modulation of cognitive abilities by cardiac phase. However, we replicated a previous finding that synchronizing stop signals at systole improved motor inhibition. This provides strong evidence that cardiac phase can facilitate inhibitory processes in the stop signal task. Although more sensitive paradigms are needed to clarify how cardiac rhythms interact with alcohol cues to influence attention and inhibition, our replication of systolic facilitation highlights the promise of cardiac cycle-based approaches in interoception research. Future studies may benefit from refining task design and considering craving states to more effectively capture the potential interoceptive influences on attention and inhibitory control.