Towards layer specific fMRI: investigating feed forward and feedback processing in area V5/MT
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2017-07-01
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en
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Abstract
High-resolution fMRI has been used to investigate layer specific feedback responses in V1. Currently, no paradigm exists for high-resolution fMRI which enables to investigate both feed forward and feedback processing in an area higher in the visual information processing hierarchy than V1. This study aimed to establish a paradigm with which those processes can be selectively elicited and manipulated in motion sensitive area V5/MT. Two different manipulations of a moving dot stimulus were used to selectively manipulate feed forward and feedback processes. To manipulate feed forward processing, three different motion coherence levels were used. Feedback processing was manipulated using an attentional task where either the motion or the color of the stimulus had to be attended. The results showed that increased motion coherence elicited increased percent signal change in V5/MT while no attention effect was observed in V5/MT. The absence of such an effect might be explained by confounds of task difficulty that could have weakened attentional influences on V5/MT activity. The here proposed paradigm demonstrates an interesting approach to investigate layer specific feed forward and feedback processes in V5/MT. However, additional investigations and improvements of the current paradigm are necessary before using it in a high-resolution fMRI setting
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Faculteit der Sociale Wetenschappen