Two theories of consciousness have different ideas about when consciousness happens and what neural processes enable conscious experience. The recurrent processing theory supports an early onset of consciousness caused by recurring loops of information between sensory areas. Contrary to this belief, the global workspace theory claims that consciousness appears later, through global recurrent loops of information between sensory and higher order brain areas such as the visual cortex and frontoparietal areas. Electrophysiological studies have found an event-related negativity arising in primary visual areas around 200 ms that correlates to awareness. This activity suits the predictions of an early onset of consciousness made by the recurrent processing theory. It is followed by a later positive amplitude appearing around 400 ms. This activity is in line with predictions made by the global workspace theory. The current study transition from visual to auditory awareness research in order to find the neural correlates of consciousness in audition. A sound detection task with tones calibrated to each participants threshold value was used in the experiment and two electrophysiological measurements of auditory awareness were found. An auditory awareness negativity that appears around 200 ms after stimulus onset and a late positivity appearing around 400 ms. Researchers disagree about if these event-related potentials correlate with awareness or unrelated cognitive mechanisms. In order to solve this problem, the current experiment was devised to test if they were affected by response conditions. A no-response paradigm with reversed response conditions was used to separate pre- and post-conscious mechanisms from the auditory awareness negativity and the late positivity. Results showed that auditory awareness negativity was independent of response condition and thus free from post-perceptual processes. The late positivity amplitude seems to be dependent on response condition but the result was inconclusive.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:his-17784 |
| Date | January 2019 |
| Creators | Fjordstig, Andréas |
| Publisher | Högskolan i Skövde, Institutionen för biovetenskap |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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