Your Brain on Imagination: It's a Lot Like Reality - Neuroscience NewsFor the study, 68 healthy participants were trained to associate a sound with an uncomfortable, but not painful, electric shock. Then, they were divided into three groups and either exposed to the same threatening sound, asked to “play the sound in their head,” or asked to imagine pleasant bird and rain sounds – all without experiencing further shocks. The researchers measured brain activity using functional magnetic resonance imaging (fMRI). Sensors on the skin measured how the body responded. In the groups that imagined and heard the threatening sounds, brain activity was remarkably similar, with the auditory cortex (which processes sound), the nucleus accumens (which processes fear) and the ventromedial prefrontal cortex (associated with risk and aversion) all lighting up. After repeated exposure without the accompanying shock, the subjects in both the real and imagined threat groups experienced what is known as “extinction,” where the formerly fear-inducing stimulus no longer ignited a fear response.