Dokument: Demographic Characteristics and Neural Mechanisms of Synaesthesia
| Titel: | Demographic Characteristics and Neural Mechanisms of Synaesthesia | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=19053 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20110914-112834-5 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Deutsch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Niccolai, Valentina [Autor] | |||||||
| Dateien: |
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| Stichwörter: | Synaesthesia | |||||||
| Dewey Dezimal-Klassifikation: | 100 Philosophie und Psychologie » 150 Psychologie | |||||||
| Beschreibung: | In synaesthetes, stimulation of one sensory pathway provokes an additional sensory experience in a different modality or sub-modality. Data concerning the demographic characteristics of synaesthetes and various aspects of the synaesthetic experience were gathered from 63 synaesthetes and compared with results of previous surveys. The following issues were addressed: prevalence of the different forms of synaesthesia, specificity of stimulus components responsible for modulating synaesthesia, implications of the high prevalence of cross-modal synaesthesia and variability of the condition over time.
To understand the role that perceptual and semantic processes play in synaesthesia, I investigated by means of electroencephalography (EEG) the time-course of grapheme-colour synaesthesia, a form in which graphemes elicit the perception of colours. EEG and behavioural measurements were collected during a cued-congruency task applied to synaesthetes and non-synaesthetes who were trained on grapheme-colour associations. An inverted priming task was used to investigate implicit bidirectional synaesthesia. Results showed longer reaction time and more negative N400 and N300 components for incongruent than for congruent trials in both groups. While non-synaesthetes largely engaged cognitive processes, synaesthetes showed congruency-related and faster perceptual activation than controls. Implicit bidirectional synaesthesia relied both on early- and late-stage cognitive processes. Event-related functional magnetic resonance imaging (fMRI) was used to shed light on the neural basis of synaesthesia and on possible shared neural mechanisms between this condition and imagery. Spatial sequence synaesthesia (SSS), which involves the perception of ordinal stimuli as arranged in peripersonal space, was investigated in a blind synaesthete. The additional synaesthetic colour perception that the subject reported for some of the stimuli, provided the opportunity to compare two different experimental and one control condition: coloured SSS, non-coloured SSS, and non-synaesthetic control. Stimuli eliciting SSS activated the occipito-parietal, infero-frontal and insular cortex. The visual colour area hOC4v was engaged when the synaesthetic experience included colour, thus indicating the continued recruitment of visual colour cortex in a late-blind synaesthete. The occipito-parietal activation suggests that the perception of spatial geometry in SSS is related to areas that are also engaged in spatial imagery in the blind as well as in sighted non-synaesthetes. | |||||||
| Lizenz: |  Urheberrechtsschutz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät » WE Psychologie » Experimentelle Biologische Psychologie | |||||||
| Dokument erstellt am: | 14.09.2011 | |||||||
| Dateien geändert am: | 14.09.2011 | |||||||
| Promotionsantrag am: | 13.05.2011 | |||||||
| Datum der Promotion: | 30.06.2011 |
