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J Hirsch, A Talati, F Valero-Cuevas; A Vision-to-Action Cortical Pathway: An fMRI Study . Invest. Ophthalmol. Vis. Sci. 2002;43(13):4746.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Many manual tasks can be performed in the absence of visual input, although the occlusion of vision often impairs task performance. This raises the question of how visual input interfaces with motor systems. Methods: We addressed this question using functional Magnetic Resonance Imaging (fMRI) and a high-dexterity task (spring compression) that was performed with and without visual input. Activity for each condition was isolated using a block-design and a statistical comparison of baseline and activity epochs. Brain regions active across two independent runs and in all 10 subjects were taken as the system elements. Results: Cortical regions that co-varied with the presence or absence of visual input included the Inferior Parietal Lobule (BA 40), Inferior Occipital (BA 18) and Middle Occipital Gyri (BA 19), Medial Frontal Gyrus (BA 6), and Cingulate Gyrus (BA 24) (ANOVA; p<0.01). The Parietal and Occipital regions showed greater voxel counts when visual input was present, whereas the Medial Frontal and Cingulate Gyri showed the greater counts when vision was occluded. Conclusion: These findings demonstrate that fine-tuned motor tasks are mediated by long-range cortical networks that vary depending on whether or not visual input is incorporated. However, when the visual system is employed, the novel and distinct cortical subsystem identified in this study integrates the visual information into a larger sensory/motor system.
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