“Follow your heart, it knows the way”: Unveiling the Impact of Heart-Brain Interactions on Free-Choice Actions

Brain-body interactions have a significant influence on various perceptual and cognitive processes, particularly decision-making in uncertain situations. Here, we specifically examine how brain-heart interactions impact voluntary decisions to initiate or refrain from actions. Our focus lies on investigating whether the Heartbeat Evoked Potential (HEP), which reflects the neural processing of cardiac signals and increases in amplitude when attention is internally directed, can predict voluntary actions. We hypothesized that a stronger modulation of the HEP would precede the execution of a free-choice action, while weaker modulation of HEP would predict action withholding. This hypothesis is based also on the observation that individuals exhibit heightened internally-directed attention during free-choice actions compared to externally-guided actions. To test this hypothesis, we conducted a study in which we simultaneously recorded cortical and cardiac signals during a modified version of the Go/No-Go task. Participants were presented with traffic lights displaying green (Go), red (No Go), or yellow (Free Choice) signals. They were instructed to freely decide whether to respond or refrain from responding to the yellow light. To introduce uncertainty, the yellow light would change to red in f ifty percent of the trials after a variable time interval, and participants would receive an auditory feedback signal if they had chosen to respond. Consistent with our hypothesis, we discovered that the amplitude of the HEP was higher when participants chose to act rather than withhold an action. These findings provide evidence that cardiac interoception plays a role in modulating the voluntary decision to initiate an action.