We examined the brain regions which were activated during mental navigation; functional magnetic resonance imaging was performed in 16 right-handed male volunteers. The anterior bank of the parieto-occipital sulcus (APO) was strongly activated in all 16 subjects examined. In group study, the retrosplenial area, the bilateral angular gyrus/occipital cortex junction, the left superior premotor area, the right parahippocampal gyrus, and the right cerebellum were activated commonly across 16 subjects. The APO region activated during mental navigation appeared to be equivalent to the visual area V6A in monkeys and to subserve egocentric spatial processes.