title: A penny for your thoughts! patterns of fMRI activity reveal the content and the spatial topography of visual mental images.
abstract: Visual mental imagery is a complex process that may be influenced by the content of mental images. Neuropsychological evidence from patients with hemineglect suggests that in the imagery domain environments and objects may be represented separately and may be selectively affected by brain lesions. In the present study, we used functional magnetic resonance imaging (fMRI) to assess the possibility of neural segregation among mental images depicting parts of an object, of an environment (imagined from a first-person perspective), and of a geographical map, using both a mass univariate and a multivariate approach. Data show that different brain areas are involved in different types of mental images. Imagining an environment relies mainly on regions known to be involved in navigational skills, such as the retrosplenial complex and parahippocampal gyrus, whereas imagining a geographical map mainly requires activation of the left angular gyrus, known to be involved in the representation of categorical relations. Imagining a familiar object mainly requires activation of parietal areas involved in visual space analysis in both the imagery and the perceptual domain. We also found that the pattern of activity in most of these areas specifically codes for the spatial arrangement of the parts of the mental image. Our results clearly demonstrate a functional neural segregation for different contents of mental images and suggest that visuospatial information is coded by different patterns of activity in brain areas involved in visual mental imagery.
authors.affiliation: Department of Psychology, "Sapienza" University of Rome, Rome, Italy; Neuropsychology Unit, IRCCS Fondazione Santa Lucia of Rome, Rome, Italy.
authors.forename: Maddalena
authors.initials: M
authors.lastname: Boccia
authors.forename: Laura
authors.initials: L
authors.lastname: Piccardi
authors.forename: Liana
authors.initials: L
authors.lastname: Palermo
authors.forename: Federico
authors.initials: F
authors.lastname: Nemmi
authors.forename: Valentina
authors.initials: V
authors.lastname: Sulpizio
authors.forename: Gaspare
authors.initials: G
authors.lastname: Galati
authors.forename: Cecilia
authors.initials: C
authors.lastname: Guariglia
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000502:physiology*; D005260:Female; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D013028:Space Perception / Q000502:physiology*; D065854:Spatial Navigation / Q000502:physiology*; D055815:Young Adult
keywords: functional magnetic resonance imaging; imagery; multivariate pattern analysis; nontopological images; topological images; visuo-spatial mental imagery