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Micro-State Dependent Perceptual Discrimination in a Metacontrast Masking Paradigm

Denomination Maîtrise universitaire interdisciplinaire en neurosciences
Defense Maîtrise : Univ. Genève, 2012
Abstract We used EEG to investigate aware perceptual discrimination thresholds as a function of pre-stimulus microstates. We employed a forced-choice discrimination task in which one of two possible targets were presented followed by a metacontrast mask. On each trail subjects indicated which target they saw and how aware they were of it. We found two microstates that doubly dissociated the aware and unaware correct trials. Their concomitant source differences found increased current density in cuneus before unaware trials. Analysis of stimulus ERPs revealed no significant surface differences between conditions. However in response-locked ERPs two topographies appeared only before unaware responses. Source differences involved a fronto-parietal network including Anterior Cingulate. We conclude that activity in early visual cortex before unaware trials prevents the upcoming stimulus to activate this area enough to ensure perception and that after response execution unaware trials elicit conflict monitoring (ACC) probably because they are treated as errors.
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Research group Laboratoire de cartographie des fonctions cérébrales
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DIAZ HERNANDEZ, Laura. Micro-State Dependent Perceptual Discrimination in a Metacontrast Masking Paradigm. Université de Genève. Maîtrise, 2012. https://archive-ouverte.unige.ch/unige:22749

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Deposited on : 2012-09-04

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