Utilize este identificador para referenciar este registo: http://hdl.handle.net/10316/92460
Título: Evidence for distinct levels of neural adaptation to both coherent and incoherently moving visual surfaces in visual area hMT
Autor: Sousa, Teresa
Sayal, Alexandre
Duarte, João V
Costa, Gabriel Nascimento Ferreira da 
Martins, Ricardo Filipe Alves 
Castelo-Branco, Miguel 
Palavras-chave: Adaptation; Bistable visual motion; Perceptual decision; Plaids; hMT+
Data: 1-Out-2018
Volume: 179
Resumo: Visual adaptation describes the processes by which the visual system alters its operating properties in response to changes in the environment. It is one of the mechanisms controlling visual perceptual bistability - when two perceptual solutions are available - by controlling the duration of each percept. Moving plaids are an example of such ambiguity. They can be perceived as two surfaces sliding incoherently over each other or as a single coherent surface. Here, we investigated, using fMRI, whether activity in the human motion complex (hMT+), a region tightly related to the perceptual integration of visual motion, is modulated by distinct forms of visual adaptation to coherent or incoherent perception of moving plaids. Our hypothesis is that exposure to global coherent or incoherent moving stimuli leads to different levels of measurable adaptation, reflected in hMT+ activity. We found that the strength of the measured visual adaptation effect depended on whether subjects integrated (coherent percept) or segregated (incoherent percept) surface motion signals. Visual motion adaptation was significant both for coherent motion and globally incoherent surface motion. Although not as strong as to the coherent percept, visual adaptation due to the incoherent percept also affects hMT+. This shows that adaptation can contribute to regulate percept duration during visual bistability, with distinct weights, depending on the type of percept. Our findings suggest a link between bistability and adaptation mechanisms, both due to coherent and incoherent motion percepts, but in an asymmetric manner. These asymmetric adaptation weights have strong implications in models of perceptual decision and may explain asymmetry of perceptual interpretation periods.
URI: http://hdl.handle.net/10316/92460
ISSN: 10538119
DOI: 10.1016/j.neuroimage.2018.06.075
Direitos: openAccess
Aparece nas coleções:I&D ICNAS - Artigos em Revistas Internacionais

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