Open this publication in new window or tab >>2025 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]
Within neuroscience, biological markers of consciousness are known as the neural correlates of consciousness (NCCs). Electrophysiological data have suggested two candidate NCCs in hearing: the auditory awareness negativity (AAN), and late positivity (LP). The AAN is linked to phenomenal awareness of sound, and the LP to post-perceptual behavioral response and executive control. Earlier research on the analogs of the AAN in both vision and touch found topographical mapping onto the cerebral hemisphere that is contralateral to stimulus source. Similar research has not been conducted on the AAN. Sound localization is the ability to perceive spatial locations of sound sources. Localization of sound in the horizontal dimension utilizes binaural cues of time and intensity differences. Sound is typically perceived from outside the head and is localized to a physical space (sound localization). When sound is perceived within the head, by using headphones, sound is instead lateralized to the left or right along an intracranial axis (sound lateralization). The thesis comprised three studies of threshold-level identification tasks, where listeners were tasked to localize laterally displaced sounds. The first study tested the NCCs to sound lateralization using a binaural click stimulus that was lateralized randomly toward either ear, presented through headphones. Then, the second study tested the NCCs to sound localization using a square pulse stimulus played from random positions in a semicircular array of thirteen horizontally displaced equidistant loudspeakers. In the third study, the NCCs to different binaural cues in sound lateralization were tested, specifically manipulating differences in time and intensity with the same stimulus and equipment used in the first study. The overall results showed that the AAN contralaterally changes in relation to experienced sound source only in sound lateralization, and only in the tested condition where binaural cues of time and intensity differences were combined. The LP showed a hemispheric contralateral effect in relation to experienced sound source, but only to sound localization. This contralateral effect may be an attentional artifact of audiovisual integration, as the loudspeakers were seen by the listeners. The thesis suggests that the NCCs to sound localization and sound lateralization differ in expression based on hearing medium.
Place, publisher, year, edition, pages
Stockholm: Department of Psychology, Stockholm University, 2025. p. 55
Keywords
neural correlates of consciousness, NCC, auditory awareness negativity, AAN, hearing, sound localization, electroencephalography, EEG, event-related potential, ERP
National Category
Psychology (Excluding Applied Psychology)
Research subject
Psychology
Identifiers
urn:nbn:se:su:diva-241493 (URN)978-91-8107-192-4 (ISBN)978-91-8107-193-1 (ISBN)
Public defence
2025-05-23, Lärosal 31, hus 4, våning 2, Albanovägen 12, Stockholm, 13:00 (English)
Opponent
Supervisors
2025-04-252025-03-312025-04-11Bibliographically approved