A PET investigation of the attribution of intentions with a nonverbal task

Several authors have demonstrated that theory of mind is associated with a cerebral pattern of activity involving the medial prefrontal cortex. This s tudy was designed to determine the cerebral regions activated during attrib ution of intention to others, a task which requires theory-of-mind skills, Eight healthy subjects performed three nonverbal tasks using comic strips w hile PET scanning was performed. One condition required subjects to attribu te intentions to the characters of the comic strips. The other two conditio ns involved only physical lose and knowledge about objects' properties: one condition involved characters, whereas the other only represented objects, The comparison of the attribution of intention condition with the physical logic with characters condition was associated with rCBF increases in the right middle and medial prefrontal cortex including Brodmann's area (BA) 9, the right inferior prefrontal cortex (BA 47), the right inferior temporal gyrus (BA 20), the left superior temporal gyrus (BA 38), the left cerebellu m, the bilateral anterior cingulate, and the middle temporal gyri (EA 21). The comparison of the physical logic with characters condition and the phys ical logic without characters condition showed the activation of the lingua l gyri (BA 17, 18, 19), the fusiform gyri (BA 37), the middle (BA 21) and s uperior (BA 22, 38) temporal gyri on both sides, and the posterior cingulat e, These data suggest that attribution of intentions to others is associate d with a complex cerebral activity involving the right medial prefrontal co rtex when a nonverbal task is used. The laterality of this function is disc ussed, (C) 2000 Academic Press.