title: Reversal of cortical information flow during visual imagery as compared to visual perception.
abstract: The role of bottom-up and top-down connections during visual perception and the formation of mental images was examined by analyzing high-density EEG recordings of brain activity using two state-of-the-art methods for assessing the directionality of cortical signal flow: state-space Granger causality and dynamic causal modeling. We quantified the directionality of signal flow in an occipito-parieto-frontal cortical network during perception of movie clips versus mental replay of the movies and free visual imagery. Both Granger causality and dynamic causal modeling analyses revealed an increased top-down signal flow in parieto-occipital cortices during mental imagery as compared to visual perception. These results are the first direct demonstration of a reversal of the predominant direction of cortical signal flow during mental imagery as compared to perception.
authors.affiliation: Department of Psychiatry, University of Wisconsin-Madison, 6001 Research Park Blvd, Madison, WI 53719, USA. Electronic address: dentico@wisc.edu.
authors.forename: Daniela
authors.initials: D
authors.lastname: Dentico
authors.affiliation: Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706, USA. Electronic address: blpcheung@gmail.com.
authors.forename: Bing Leung
authors.initials: BL
authors.lastname: Cheung
authors.affiliation: Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706, USA. Electronic address: jchang38@wisc.edu.
authors.forename: Jui-Yang
authors.initials: JY
authors.lastname: Chang
authors.affiliation: Department of Psychiatry, University of Wisconsin-Madison, 6001 Research Park Blvd, Madison, WI 53719, USA. Electronic address: jeffreyguokas@gmail.com.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Guokas
authors.affiliation: Department of Psychiatry, University of Wisconsin-Madison, 6001 Research Park Blvd, Madison, WI 53719, USA; Coma Science Group, Cyclotron Research Center and Neurology Department, University of Liège, Allée du 6 août no 8, 4000 Liège, Belgium. Electronic address: mboly@ulg.ac.be.
authors.forename: Melanie
authors.initials: M
authors.lastname: Boly
authors.affiliation: Department of Psychiatry, University of Wisconsin-Madison, 6001 Research Park Blvd, Madison, WI 53719, USA. Electronic address: gtononi@wisc.edu.
authors.forename: Giulio
authors.initials: G
authors.lastname: Tononi
authors.affiliation: Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706, USA. Electronic address: vanveen@engr.wisc.edu.
authors.forename: Barry
authors.initials: B
authors.lastname: Van Veen
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008297:Male; D015233:Models, Statistical; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: Bottom-up; Dynamic causal modeling; Granger causality; Imagery; Perception; Top-down