Credit: Photo courtesy of Bradley Peterson, M
Brain activity of spider phobic people during repeated presentation of pictures of spiders - when they were aware of them (left column), and when they were not aware of them (right column). The phobic people processed the spider pictures significantly more when they were not aware of them, particularly in brain systems (including frontal cortex and caudate nucleus) that support regulation of fear and its associated behavioral responses. These are 2D slices positioned parallel to the floor in a standing person, with the forehead at the top and the back of the head at the bottom of each slice.