As the heart, lungs, gut and other organs transmit information to the brain, they affect how we perceive and interact with our environment in surprisingly profound ways. Recent studies of the heart in particular have given scientists new insights into the role that the body’s most basic processes play in defining our experience of the world.
Cardiac activity can be divided into two phases: systole, when the heart muscle contracts and pumps out blood, followed by diastole, when it relaxes and refills with blood.
…[Neuroscientist Sarah Garfinkel] and her team conditioned test subjects to associate some shapes with a mild electric shock, and then presented them with those shapes — as well as more neutral ones — during systole and diastole. The expectation was that people would always exhibit more fear of the shapes associated with the shock. Instead, the participants responded more fearfully to all the shapes that were presented at systole. “And that overshadows them learning, initially, what’s associated with shock or not shock,” Garfinkel said. “There’s something inherent about the thing that is presented when the heart is beating which is more fearful. And that’s so strong. That’s such a strong effect, it really blew my mind.”
…[They] have also found that systole is more likely to enhance fear processing in people with anxiety. The researchers now hope that their work can guide therapies for certain phobias and post-traumatic stress disorder.