The medial prefrontal cortex is believed to be involved in emotional experiences, but also in situations in which attention and self-monitoring is required. Therefore, it might be that the medial prefrontal cortex is not only activated by the emotional state per se, but rather through the task requirements that were used to induce emotions in the laboratory. The present study investigated the change of oxygenation in the left and right prefrontal cortex measured with near-infrared spectroscopy (NIRS) from 14 subjects during two kinds of emotional induction, which differed in the self-monitoring requirements. The task with the higher self-monitoring requirements resulted in an increased concentration of oxygenated hemoglobin (O(2)HB). This activation pattern was not observed during the emotional induction with the fewer self-monitoring requirements, although the subjective ratings indicated that both tasks induced comparable emotional states. The results indicate that task requirements should be taken into account when investigating the neural substrate of emotions.