Ultra-high field fMRI of visual mental imagery in typical imagers and aphantasic individuals

Abstract We used ultra-high field 7T fMRI to establish the neural circuits involved in visual mental imagery and perception, and to elucidate the neural mechanisms associated with imagery absence in congenital aphantasia. Ten typical imagers and 10 aphantasic individuals performed imagery and perceptual tasks in five domains: object shape, object color, written words, faces, and spatial relationships. In typical imagers, imagery tasks activated left-hemisphere fronto-parietal areas, a domain-general area in the left fusiform gyrus (the Fusiform Imagery Node), together with the relevant domain-preferring areas in the ventral temporal cortex. In aphantasic individuals, imagery activated similar areas, but the Fusiform Imagery Node was functionally disconnected from fronto-parietal areas. Our results unveil the domain-general and domain-specific circuits of visual mental imagery, their functional disorganization in aphantasia, and support the general hypothesis that subjective visual experience - whether perceived or imagined - depends on the integrated activity of high-level visual cortex and fronto-parietal networks.