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.
Acknowledgements
We thank speech therapist Gabriela Leal who provided us data regarding language evaluation of patients J.T. and A.B.
Disclosure statement
No potential conflict of interest was reported by the authors.
ORCID
Jorge Almeida http://orcid.org/0000-0002-6302-7564
Lénia Amaral http://orcid.org/0000-0002-0631-7944
Diana Aguiar de Sousa http://orcid.org/0000-0002-6702-7924
Isabel Pavão Martins http://orcid.org/0000-0002-9611-7400