Neural correlates of imagery induced by the ambient sound

Based on the assumption that better imagery while listening to the sound is related with higher sense of presence, neural correlates of imagery induced by the ambient sound that represents scenery (e.g. ocean waves, river stream, jungle, city traffic) were investigated by functional Magnetic Resonance Imaging (fMRI). During the fMRI experiment, brain activity was recorded while participants listened to the sound with eyes closed. Their button responses indicating the imagery levels were also recorded. Enhanced activities for the ambient sound condition relative to the noise condition were found in brain regions involved with auditory perception (the superior temporal gyrus). Imagery level correlated activities were found in brain regions involved with simulation of both biological and non-biological events (the lateral premotor cortex, the inferior frontal gyrus, and the inferior parietal lobe). The present study suggests that the level of imagery induced by the ambient sound is related with the level of neural activity in brain regions involved with the events simulation. The possibility of measuring the level of presence by assessing neural activity is implicated.