Human Navigation Without and With Vision - the Role of Visual Experience and Visual Regions

Abstract

Human navigation relies on a wide range of visual retinotopic cortical regions yet the precise role that these regions play in navigation remains unclear. Are these regions mainly sensory input channels or also modality-independent spatial processing centers? Accordingly, will they be recruited for navigation also without vision, such as via audition? Will visual experience, or the lack thereof, affect this recruitment? Sighted, congenitally blind and sighted-blindfolded participants actively navigated virtual mazes during fMRI scanning before and after navigating them in the real world. Participants used the EyeCane visual-to-auditory navigation aid for non-visual navigation.\n\nWe found that retinotopic regions, including both dorsal stream regions (e.g. V6) and primary regions (e.g. peripheral V1), were selectively recruited for non-visual navigation only after the participants mastered the EyeCane demonstrating rapid plasticity for non-visual navigation. The hippocampus, considered the navigation networks core, displayed negative BOLD in all groups.\n\nOur results demonstrate the robustness of the retinotopic nodes modality-independent spatial role in non-visual human navigation to lifelong visual-deprivation, demonstrating that visual input during development is not required for their recruitment. Furthermore, our results with the blindfolded group demonstrate this recruitments robustness even to brief blindfolding, but only after brief training, demonstrating rapid task based plasticity. These results generalize the wider framework of task-selectivity rather than input-modality as a brain organization principle to dorsal-stream retinotopic areas and even for the first time to the primary visual cortex.\n\nHighlightsO_LIBoth visual and non-visual navigation recruit retinotopic regions\nC_LIO_LIAfter training blindfolded subjects selectively recruit V1 & V6 for navigation\nC_LIO_LIThis holds also for participants with no visual experience (congenitally blind)\nC_LIO_LIThe medial temporal lobe showed non-selective Negative BOLD in all groups\nC_LI\n\nDeclaration of interestsAll authors declare that they have no conflicts of interests.