Riding the alpha wave - how auditory perception is shaped by oscillatory activity

Lade...
Vorschaubild
Dateien
Dissertation_N_Müller.pdf
Dissertation_N_Müller.pdfGröße: 9.06 MBDownloads: 506
Datum
2011
Autor:innen
Herausgeber:innen
Kontakt
ISSN der Zeitschrift
Electronic ISSN
ISBN
Bibliografische Daten
Verlag
Schriftenreihe
Auflagebezeichnung
DOI (zitierfähiger Link)
ArXiv-ID
Internationale Patentnummer
Angaben zur Forschungsförderung
Projekt
Open Access-Veröffentlichung
Open Access Green
Sammlungen
Core Facility der Universität Konstanz
Gesperrt bis
Titel in einer weiteren Sprache
Einfluss der auditorischen Alpha-Aktivität auf auditorische Wahrnehmung
Forschungsvorhaben
Organisationseinheiten
Zeitschriftenheft
Publikationstyp
Dissertation
Publikationsstatus
Published
Erschienen in
Zusammenfassung

It is known since early psychophysiological research and an intriguing matter of fact that identical stimuli can elicit different neuronal responses and lead to varying percepts. The brain’s current state, which is reflected in the pattern of ongoing neuronal oscillations, thereby plays a key role. Growing evidence in the visual/somatosensory modality shows that particularly the alpha rhythm (an oscillation at about 10 Hz) defines the excitability of a certain brain region and systematically impacts on perception. While the decrease of alpha power points to increased excitability that facilitates perception the increase of alpha power has been related to the inhibition of the accordant brain region resulting in an inhibition or gating of perception. For the auditory modality, however, no such association has been established yet. Three studies were designed to investigate whether also auditory perception is dependent on the modulation of auditory alpha oscillations.

The first study was carried out to examine the top-down modulation of the auditory cortex mediated by voluntary attention. Participants were visually cued to attend to either the left or right ear and after a short anticipation phase they had to distinguish target from standard tones at the respective ear. In line with the notion that an increase in alpha power reflects the gating of sensory information a prominent increase of low auditory alpha power in the hemisphere predominantly processing the to-be-ignored sound was found. The alpha power enhancement was further related to an increased synchronization between the strongly modulated auditory cortex and the right frontal eye fields described as key structure of the spatial attention network. Importantly, the condition-specific alpha power modulation in the auditory cortex was already present during anticipation of the auditory stimuli and thus mediated by mere top-down processes.

These results led to another research question that is whether auditory perception is influenced automatically by bottom-up modulation of auditory alpha power. To address this within the second study the continuous perception of a phantom sound in tinnitus patients was altered by stimulation of the auditory cortex with Transcranial Magnetic Stimulation. The question was whether the perceptual changes are reflected in the modulation of auditory alpha activity. Strong decreases in tinnitus loudness were indeed related to increases in auditory alpha power at the stimulated site. This is in accordance with the notion that an increase of auditory alpha power is a crucial mechanism for gating auditory perception. The finding is further in line with the results of the first study that related increased auditory alpha power to a gating of external auditory stimuli.

The third study was designed to examine whether and how oscillatory alpha activity is modulated when an auditory illusion is generated in healthy students. Therefore, auditory oscillatory activity to invariant sounds embedded in familiar as well as unfamiliar music was compared. Based on the fact that perception of continuity is facilitated by experience, it was hypothesized that noise within familiar music would be more likely to elicit a continuous percept of music than noise within unfamiliar music. Results indicated that this was indeed the case and that during the illusory perception of music alpha activity was reduced in the auditory cortex. This finding points to an increase of auditory cortex excitability favouring the experience of an illusory percept. Importantly, in this study it was shown that a decrease of auditory alpha power facilitated auditory perception emphasizing that auditory alpha power can indeed be modulated in both directions to either facilitate or gate perception. In addition to the auditory alpha power modulations, the auditory cortex increased its communication with the parahippocampal formation that likely stores the memory contents associated with the music illusion. It seems thus likely that neuronal activity in the highly excitable auditory cortex was shaped through the auditory-parahippocampal communication so that the illusion of continuing music was generated.

Based on the three studies it can be concluded that auditory perception indeed depends on oscillatory alpha activity in the auditory cortex. Furthermore, the modulation of auditory alpha activity is related to the communication between the auditory cortex and non-auditory brain regions that are specific for different percepts or tasks (such as the spatial attention network or memory network). These findings are consistent with and extend findings concerning the impact of specific oscillatory activity patterns on perception from other modalities like the visual or somatosensory to the auditory. Last but not least, determining the signatures in auditory and non-auditory brain regions that are associated with improved auditory perception or pathological conditions such as tinnitus will serve as a basis for the development of effective interventions.

Zusammenfassung in einer weiteren Sprache

Schon seit Beginn psychophysiologischer Forschung ist bekannt, dass identische Reize unterschiedliche neuronale Antworten und Perzepte auslösen können. Der momentane Zustand des Gehirns, der sich in einem spezifischen Muster neuronaler Oszillationen widerspiegelt, scheint dabei eine Schlüsselrolle zu spielen. In der Tat konnten Studien im visuellen und auch somatosensorischen System zeigen, dass insbesondere Oszillationen im Alpha Band (etwa 10 Hz), die Erregbarkeit von Hirnregionen bestimmen und systematisch unsere Wahrnehmung beeinflussen. Eine Abnahme von Alpha-Power wird dabei mit erhöhter Erregbarkeit in Verbindung gebracht und begünstigt die Wahrnehmung. Erhöhte Alpha-Power hingegen weist auf Hemmung der entsprechenden Hirnregion hin und unterdrückt Wahrnehmungsinhalte. Solch ein Zusammenhang konnte im auditorischen System noch nicht gezeigt werden und war Forschungsgegenstand der vorliegenden Arbeit. Dazu wurden die drei folgenden Studien entworfen.

Die erste Studie wurde mit dem Ziel konzipiert eine mögliche Top-down Modulation des auditorischen Kortex durch willentliche Aufmerksamkeit aufzudecken. Probanden wurden mittels eines visuellen Hinweisreizes gebeten, sich auf das rechte oder linke Ohr zu konzentrieren und nach einer kurzen Antizipationsphase am angezeigten Ohr Zielreize von Standardtönen zu unterscheiden. Es konnte gezeigt werden, dass Alpha-Power in der Hemisphäre, die bevorzugt den zu ignorierenden Ton verarbeitet, deutlich erhöht ist. Das passt zu Befunden aus anderen Modalitäten, die einen Zusammenhang zwischen erhöhter Alpha Power und der Hemmung von externen sensorischen Reizen feststellen konnten. Darüber hinaus war diese Power Erhöhung mit einer verstärkten Synchronisation zwischen dem auditorischen Kortex und dem rechten Frontalen Augenfeld, das eine wichtige Komponente des räumlichen Aufmerksamkeitsnetzes darstellt, assoziiert. Die bedingungsspezifische Alpha-Power Modulation war bereits in der Antizipationsphase, also vor der auditorischen Stimulation zu beobachten und daher zweifellos durch Top-down Prozesse vermittelt.
Die zweite Studie befasste sich mit der Frage, ob durch eine direkte Modulation der auditorischen Alpha-Aktivität, auditorische Wahrnehmung verändert werden kann. Dazu wurde bei Patienten, die unter einem chronischen Tinnitus leiden, der auditorische Kortex mittels Transkranieller Magnetstimulation (TMS) stimuliert. Es wurde untersucht, ob durch die Stimulation gezielt Alpha-Power im auditorischen Kortex moduliert wird und inwiefern eine solche Modulation die Lautstärke des Tinnitus verändert. Eine deutliche Abnahme des Tinnitus ging tatsächlich mit erhöhter Alpha-Power im stimulierten auditorischen Kortex einher. Auch dieser Befund deckt sich sehr schön mit der Annahme, dass die Erhöhung von Alpha Power ein entscheidender Mechanismus ist, Wahrnehmungsinhalte zu unterdrücken.

Die dritte Studie wurde entworfen, um der Frage nachzugehen, ob und wie Alpha-Power moduliert wird, wenn gesunde Probanden eine auditorische Illusion wahrnehmen. Dazu wurde bekannte und unbekannte Musik durch kurze Rauschperioden unterbrochen. Bevorzugt im Kontext bekannter Musik entsteht eine kontinuierliche Wahrnehmung der Musik durch die Rauschperioden hindurch. Neurophysiologische Ergebnisse zeigen, dass Alpha-Power im auditorischen Kortex während Rauschperioden im Kontext bekannter Musik, also während der illusorischen Musik-Wahrnehmung, deutlich reduziert ist. Diese Alpha-Power Reduktion weist auf eine Erhöhung von Exzitabilität im auditorischen Kortex hin und begünstigt die Wahrnehmung des illusorischen Perzepts. Wesentlich ist, dass in dieser Studie gezeigt werden konnte, dass verringerte Alpha-Power auditorische Wahrnehmung begünstigte. Auditorische Alpha-Power kann also in beide Richtungen moduliert werden, um Wahrnehmung zu unterdrücken oder zu begünstigen. Zusätzlich zu den auditorischen Alpha Power Modulationen, verstärkte sich die Kommunikation zwischen dem Parahippocampalen Komplex, der vermutlich mit der Musik assoziierte Gedächtnisinhalte speichert, und dem auditorischen Kortex. Durch diese Kommunikation könnte möglicherweise das Muster neuronaler Aktivität im hoch erregbaren auditorischen Kortex so geformt werden, dass eine Illusion von kontinuierlicher Musik entsteht.

Basierend auf diesen drei Studien kann man zusammenfassen, dass auditorische Wahrnehmung tatsächlich von oszillatorischer Alpha-Power im auditorischen Kortex abhängt. Außerdem, hängt die Modulation der Alpha-Power mit der Kommunikation zwischen dem auditorischen Kortex und nicht-auditorischen Hirnregionen zusammen, die spezifisch für verschiedene Wahrnehmungsinhalte oder Aufgaben ist (Netzwerk räumlicher Aufmerksamkeit, Gedächtnisnetzwerk). Diese Erkenntnisse passen zu Studien in andern Modalitäten wie dem visuellen System und erweitern den bedeutenden Einfluss bestimmter oszillatorischer Muster auch auf das auditorische System. Nicht zuletzt könnte die Bestimmung spezifischer oszillatorischer Muster sowohl in auditorischen als auch zwischen auditorischen und nicht-auditorischen Hirnregionen, die mit verbesserter Wahrnehmung oder pathologischen Zuständen wie etwa Tinnitus zusammenhängen, als Basis für die Entwicklung effektiver Interventionen dienen.

Fachgebiet (DDC)
150 Psychologie
Schlagwörter
Konferenz
Rezension
undefined / . - undefined, undefined
Zitieren
ISO 690MÜLLER, Nadia, 2011. Riding the alpha wave - how auditory perception is shaped by oscillatory activity [Dissertation]. Konstanz: University of Konstanz
BibTex
@phdthesis{Muller2011Ridin-17462,
  year={2011},
  title={Riding the alpha wave - how auditory perception is shaped by oscillatory activity},
  author={Müller, Nadia},
  address={Konstanz},
  school={Universität Konstanz}
}
RDF
<rdf:RDF
    xmlns:dcterms="http://purl.org/dc/terms/"
    xmlns:dc="http://purl.org/dc/elements/1.1/"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:bibo="http://purl.org/ontology/bibo/"
    xmlns:dspace="http://digital-repositories.org/ontologies/dspace/0.1.0#"
    xmlns:foaf="http://xmlns.com/foaf/0.1/"
    xmlns:void="http://rdfs.org/ns/void#"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema#" > 
  <rdf:Description rdf:about="https://kops.uni-konstanz.de/server/rdf/resource/123456789/17462">
    <dc:rights>terms-of-use</dc:rights>
    <dspace:isPartOfCollection rdf:resource="https://kops.uni-konstanz.de/server/rdf/resource/123456789/43"/>
    <dcterms:hasPart rdf:resource="https://kops.uni-konstanz.de/bitstream/123456789/17462/2/Dissertation_N_M%c3%bcller.pdf"/>
    <dcterms:available rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2011-12-21T10:09:25Z</dcterms:available>
    <dc:creator>Müller, Nadia</dc:creator>
    <dcterms:alternative>Einfluss der auditorischen Alpha-Aktivität auf auditorische Wahrnehmung</dcterms:alternative>
    <bibo:uri rdf:resource="http://kops.uni-konstanz.de/handle/123456789/17462"/>
    <dcterms:isPartOf rdf:resource="https://kops.uni-konstanz.de/server/rdf/resource/123456789/43"/>
    <void:sparqlEndpoint rdf:resource="http://localhost/fuseki/dspace/sparql"/>
    <dc:language>eng</dc:language>
    <dcterms:abstract xml:lang="eng">It is known since early psychophysiological research and an intriguing matter of fact that identical stimuli can elicit different neuronal responses and lead to varying percepts. The brain’s current state, which is reflected in the pattern of ongoing neuronal oscillations, thereby plays a key role. Growing evidence in the visual/somatosensory modality shows that particularly the alpha rhythm (an oscillation at about 10 Hz) defines the excitability of a certain brain region and systematically impacts on perception. While the decrease of alpha power points to increased excitability that facilitates perception the increase of alpha power has been related to the inhibition of the accordant brain region resulting in an inhibition or gating of perception. For the auditory modality, however, no such association has been established yet. Three studies were designed to investigate whether also auditory perception is dependent on the modulation of auditory alpha oscillations.&lt;br /&gt;&lt;br /&gt;The first study was carried out to examine the top-down modulation of the auditory cortex mediated by voluntary attention. Participants were visually cued to attend to either the left or right ear and after a short anticipation phase they had to distinguish target from standard tones at the respective ear. In line with the notion that an increase in alpha power reflects the gating of sensory information a prominent increase of low auditory alpha power in the hemisphere predominantly processing the to-be-ignored sound was found. The alpha power enhancement was further related to an increased synchronization between the strongly modulated auditory cortex and the right frontal eye fields described as key structure of the spatial attention network. Importantly, the condition-specific alpha power modulation in the auditory cortex was already present during anticipation of the auditory stimuli and thus mediated by mere top-down processes.&lt;br /&gt;&lt;br /&gt;These results led to another research question that is whether auditory perception is influenced automatically by bottom-up modulation of auditory alpha power. To address this within the second study the continuous perception of a phantom sound in tinnitus patients was altered by stimulation of the auditory cortex with Transcranial Magnetic Stimulation. The question was whether the perceptual changes are reflected in the modulation of auditory alpha activity. Strong decreases in tinnitus loudness were indeed related to increases in auditory alpha power at the stimulated site. This is in accordance with the notion that an increase of auditory alpha power is a crucial mechanism for gating auditory perception. The finding is further in line with the results of the first study that related increased auditory alpha power to a gating of external auditory stimuli.&lt;br /&gt;&lt;br /&gt;The third study was designed to examine whether and how oscillatory alpha activity is modulated when an auditory illusion is generated in healthy students. Therefore, auditory oscillatory activity to invariant sounds embedded in familiar as well as unfamiliar music was compared. Based on the fact that perception of continuity is facilitated by experience, it was hypothesized that noise within familiar music would be more likely to elicit a continuous percept of music than noise within unfamiliar music. Results indicated that this was indeed the case and that during the illusory perception of music alpha activity was reduced in the auditory cortex. This finding points to an increase of auditory cortex excitability favouring the experience of an illusory percept. Importantly, in this study it was shown that a decrease of auditory alpha power facilitated auditory perception emphasizing that auditory alpha power can indeed be modulated in both directions to either facilitate or gate perception. In addition to the auditory alpha power modulations, the auditory cortex increased its communication with the parahippocampal formation that likely stores the memory contents associated with the music illusion. It seems thus likely that neuronal activity in the highly excitable auditory cortex was shaped through the auditory-parahippocampal communication so that the illusion of continuing music was generated.&lt;br /&gt;&lt;br /&gt;Based on the three studies it can be concluded that auditory perception indeed depends on oscillatory alpha activity in the auditory cortex. Furthermore, the modulation of auditory alpha activity is related to the communication between the auditory cortex and non-auditory brain regions that are specific for different percepts or tasks (such as the spatial attention network or memory network). These findings are consistent with and extend findings concerning the impact of specific oscillatory activity patterns on perception from other modalities like the visual or somatosensory to the auditory. Last but not least, determining the signatures in auditory and non-auditory brain regions that are associated with improved auditory perception or pathological conditions such as tinnitus will serve as a basis for the development of effective interventions.&lt;br /&gt;</dcterms:abstract>
    <dcterms:issued>2011</dcterms:issued>
    <dc:contributor>Müller, Nadia</dc:contributor>
    <dc:date rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2011-12-21T10:09:25Z</dc:date>
    <dcterms:title>Riding the alpha wave - how auditory perception is shaped by oscillatory activity</dcterms:title>
    <dcterms:rights rdf:resource="https://rightsstatements.org/page/InC/1.0/"/>
    <foaf:homepage rdf:resource="http://localhost:8080/"/>
    <dspace:hasBitstream rdf:resource="https://kops.uni-konstanz.de/bitstream/123456789/17462/2/Dissertation_N_M%c3%bcller.pdf"/>
  </rdf:Description>
</rdf:RDF>
Interner Vermerk
xmlui.Submission.submit.DescribeStep.inputForms.label.kops_note_fromSubmitter
Kontakt
URL der Originalveröffentl.
Prüfdatum der URL
Prüfungsdatum der Dissertation
December 5, 2011
Finanzierungsart
Kommentar zur Publikation
Allianzlizenz
Corresponding Authors der Uni Konstanz vorhanden
Internationale Co-Autor:innen
Universitätsbibliographie
Ja
Begutachtet
Diese Publikation teilen