Selective attention is a crucial function that encompasses all perceptual modalities and which enables us to focus on the behaviorally relevant information and ignore the rest. The main goal of the thesis is to test well-established hypotheses about the mechanisms of visual selective attention in the auditory domain using behavioral and neuroimaging methods. Two fMRI studies (Experiments 1 and 2) test the hypothesis of feature-specific attentional enhancement. This hypothesis states that when attending to an object or a feature, there should be an enhancement of the response in the sensory region that is sensitive to that object or feature. Experiment 1 investigated feature-specific attentional modulation mainly within the tonotopic fields around primary auditory cortex. Experiment 2 investigated feature-specific attentional modulation mainly around non-primary auditory cortex, when attending to frequency modulation or motion of the same auditory object. Experiment 1 showed evidence for feature-specific enhancement, while Experiment 2 did not. The role of competition among concurrent auditory objects as a necessary factor in driving feature-specific enhancement is discussed. A second hypothesis from vision research is that spatial perception and attention is much more precise in the centre than in the periphery. Experiment 3 used a masking release paradigm to investigate whether the acuity of auditory spatial attention was similarly increased in the midline. Although location discrimination of sounds segregated by inter-aural time differences was more precise at the midline than at the periphery, spatial attention was not. Therefore for this task at least there was no effect of eccentricity on auditory spatial attention. The results of these three studies are discussed in view of selective attention as a flexible process that operates in different ways according to the specifics of the task.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:514736 |
| Date | January 2009 |
| Creators | Paltoglou, Aspasia Eleni |
| Publisher | University of Nottingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://eprints.nottingham.ac.uk/10697/ |
Page generated in 0.0019 seconds