A region at the front of the brain’s right hemisphere, the prefrontal cortex, plays a critical role in how the human brain processes emotions. Data from previous studies of brain lesions (areas of damage that alter the brain’s ability to generate normal emotions) and data from functional brain imaging studies have delineated the extent of the area involved. However, a recent University of Iowa study is the first to investigate human emotion processing by the right prefrontal cortex at the level of individual brain cells. Interestingly, while monitoring single neurons in the right prefrontal cortex, the researchers found that these cells responded remarkably rapidly to unpleasant images, which included pictures of mutilations and scenes of war. Happy or neutral pictures did not cause the same rapid response from the neurons.