title: Looming sensitive cortical regions without V1 input: evidence from a patient with bilateral cortical blindness.
abstract: Fast and automatic behavioral responses are required to avoid collision with an approaching stimulus. Accordingly, looming stimuli have been found to be highly salient and efficient attractors of attention due to the implication of potential collision and potential threat. Here, we address the question of whether looming motion is processed in the absence of any functional primary visual cortex and consequently without awareness. For this, we investigated a patient (TN) suffering from complete, bilateral damage to his primary visual cortex. Using an fMRI paradigm, we measured TN's brain activation during the presentation of looming, receding, rotating, and static point lights, of which he was unaware. When contrasted with other conditions, looming was found to produce bilateral activation of the middle temporal areas, as well as the superior temporal sulcus and inferior parietal lobe (IPL). The latter are generally thought to be involved in multisensory processing of motion in extrapersonal space, as well as attentional capture and saliency. No activity was found close to the lesioned V1 area. This demonstrates that looming motion is processed in the absence of awareness through direct subcortical projections to areas involved in multisensory processing of motion and saliency that bypass V1.
authors.affiliation: Laboratory of Experimental Neuropsychology, Neurology Clinic, Department of Clinical Neuroscience, University of Geneva Geneva, Switzerland ; Brain and Language Lab, Department of Clinical Neuroscience, University of Geneva Geneva, Switzerland.
authors.forename: Alexis
authors.initials: A
authors.lastname: Hervais-Adelman
authors.affiliation: Laboratory of Experimental Neuropsychology, Neurology Clinic, Department of Clinical Neuroscience, University of Geneva Geneva, Switzerland ; Faculty of Psychology and Educational Sciences, University of Geneva Geneva, Switzerland.
authors.forename: Lore B
authors.initials: LB
authors.lastname: Legrand
authors.affiliation: Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University Maastricht, Netherlands.
authors.forename: Minye
authors.initials: M
authors.lastname: Zhan
authors.affiliation: Department of Psychology, University of Torino Torino, Italy ; Cognitive and Affective Neuroscience Laboratory, Center of Research on Psychology in Somatic Diseases, Tilburg University Tilburg, Netherlands ; Department of Experimental Psychology, University of Oxford Oxford, UK.
authors.forename: Marco
authors.initials: M
authors.lastname: Tamietto
authors.affiliation: Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University Maastricht, Netherlands.
authors.forename: Beatrice
authors.initials: B
authors.lastname: de Gelder
authors.affiliation: Laboratory of Experimental Neuropsychology, Neurology Clinic, Department of Clinical Neuroscience, University of Geneva Geneva, Switzerland ; Faculty of Psychology and Educational Sciences, University of Geneva Geneva, Switzerland ; School of Psychology, University of Queensland Brisbane, QLD, Australia.
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Pegna
keywords: MT/V5; blindsight; cortical blindness; fMRI; hemianopia; looming; motion