Visual and visuomotor processing of hands and tools as a case study of cross talk between the dorsal and ventral streams |
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Authors: | Jorge Almeida Lénia Amaral Frank E. Garcea Diana Aguiar de Sousa Shan Xu Bradford Z. Mahon |
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Affiliation: | 1. Faculty of Psychology and Educational Sciences, University of Coimbra, Coimbra, Portugal;2. Faculty of Psychology and Educational Sciences, Proaction Laboratory, University of Coimbra, Coimbra, Portugal;3. Faculty of Psychology and Educational Sciences, Proaction Laboratory, University of Coimbra, Coimbra, Portugal;4. Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY, USA;5. Center for Visual Science, University of Rochester, Rochester, NY, USA;6. Faculty of Medicine, Laboratório de Estudos da Linguagem, Centro de Estudos Egas Moniz, University of Lisbon, Hospital Santa Maria, Lisbon, Portugal;7. School of Psychology, Beijing Normal University, Beijing, People’s Republic of China;8. Department of Neurosurgery, University of Rochester, Rochester, NY, USA |
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Abstract: | A major principle of organization of the visual system is between a dorsal stream that processes visuomotor information and a ventral stream that supports object recognition. Most research has focused on dissociating processing across these two streams. Here we focus on how the two streams interact. We tested neurologically-intact and impaired participants in an object categorization task over two classes of objects that depend on processing within both streams—hands and tools. We measured how unconscious processing of images from one of these categories (e.g., tools) affects the recognition of images from the other category (i.e., hands). Our findings with neurologically-intact participants demonstrated that processing an image of a hand hampers the subsequent processing of an image of a tool, and vice versa. These results were not present in apraxic patients (N?=?3). These findings suggest local and global inhibitory processes working in tandem to co-register information across the two streams. |
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Keywords: | Apraxia dorsal stream hands tools ventral stream |
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