Persistent neural activity in the human frontal cortex when maintaining space that is “off the map”

During the maintenance of visuospatial information, neural activity in the frontal eye field (FEF) persists and is thought to be an important neural mechanism for visual working memory. We used functional magnetic resonance imaging to examine whether human FEF activity persists when maintaining auditory space and whether it is selective for retinal versus extra-retinal space. Subjects performed an audiospatial working-memory task using sounds recorded from microphones placed in each subject's ear canals, which preserved the interaural time and level differences that are critical for sound localization. Putative FEF activity persisted when maintaining auditory-cued space, even for locations behind the head to which it is impossible to make saccades. Therefore, human FEF activity represents both retinal and extra-retinal space.