University of Twente Student Theses


Early electrophysiological activity of the visual cortex does not reflect access to visual awareness

Lauffs, M.M. (2012) Early electrophysiological activity of the visual cortex does not reflect access to visual awareness.

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Abstract:Current models of visual awareness emphasize the role of the fronto-parietal cortex in the emergence of reportable visual awareness. However, these models are unclear about whether the strength of early visual cortex activity is of importance for visual awareness once a minimum threshold is exceeded. Electrophysiological investigations of this matter have produced differing results. The current study investigated whether the amplitude of the two earliest components of the visual event-related potential (C1, P1) correlates with the level of visual awareness. Symbolic pre-cues were used to control the focus of visuo-spatial attention. Identical visual stimuli were briefly flashed on a screen and subsequently masked using metacontrast. Subjects indicated the experienced visibility of the stimuli in a two-alternative forced-choice task after each stimulus presentation, allowing for conclusions concerning their level of visual awareness. The level of visual awareness did not significantly affect the amplitude of the C1 and P1 components. In line with current models of visual awareness, this finding suggests that early responding of the visual cortex is inessential for introspective access to visual awareness once a minimum threshold of activity is exceeded. It can be hypothesized, however, that C1 and P1 might be of importance to processes preceding the access stage.
Item Type:Essay (Master)
Faculty:BMS: Behavioural, Management and Social Sciences
Subject:77 psychology
Programme:Psychology MSc (66604)
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