The somatic marker hypothesis: revisiting the role of the 'body-loop' in decision-making

The somatic marker hypothesis is one of the most influential neurocognitive theories of emotion and decision-making. A key aspect of the somatic marker hypothesis is the 'body-loop', which is the claim that emotive events that are expressed in the body can influence decision-making via afferent feedback to the brain. The body-loop has often been the subject of debate. However, evidence for the neural and peripheral mechanisms that support interactions between bodily states and cognitive functions has consistently emerged. The purpose of this article is to outline an updated neurophysiological account of how somatic states may be triggered, and how they bias decisions through afferent feedback. We largely focus on vagus nerve-dependent feedback mechanisms, which demonstrate how interoceptive signals can shape high order cognition and goal-directed behavior.