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  1. Book ; Thesis: Neuronale Prozesse auditorisch induzierter visueller Wahrnehmungssteigerung

    Tyll, Sascha

    2010  

    Abstract: Die vorliegende Dissertation beschäftigt sich mit der Analyse audiovisueller Interaktionsprozesse. In drei Experimenten (N = 14; 12; 13) wurde mit Hilfe von psychophysischen Methoden und bildgebenen Verfahren der Einfluss auditorischer Stimuli auf das ... ...

    Title translation Neural processes in auditory induced visual perception modulation
    Abstract Die vorliegende Dissertation beschäftigt sich mit der Analyse audiovisueller Interaktionsprozesse. In drei Experimenten (N = 14; 12; 13) wurde mit Hilfe von psychophysischen Methoden und bildgebenen Verfahren der Einfluss auditorischer Stimuli auf das visuelle Detektionsverhalten in Abhängigkeit der Salienz visueller Zielreize untersucht. Es konnte gezeigt werden, dass das visuelle Detektionsverhalten durch einen irrelevanten auditorischen Stimulus positiv beeinflusst werden kann und dass dieser multimodale Integrationsprozess nur bei niedrig salienten visuellen Stimuli beobachtet werden konnte. Als neuronales Korrelat dieses multimodalen Integrationseffektes konnte, unter Anwendung der funktionellen Magnetresonanztomographie (fMRT), ein Netzwerk aus kortikalen multisensorischen Konvergenzzonen und modalitätsassoziierten Arealen identifiziert werden. Die Modulation neuronaler Strukturen beschränkte sich nicht nur auf kortikale Gebiete; sie konnte auch in unisensorischen thalamischen Kerngebieten detektiert werden. Mit Hilfe der Elektroenzephalografie, welche die zeitlich-dynamischen Prozesse des ermittelten Verhaltensinteraktionsprozesses identifizieren sollte, konnte gezeigt werden, dass die Salienz eines visuellen Stimulus vermutlich Filtermechanismen auf Grund von thalamischen Interaktionsprozessen in auditorischen Arealen moduliert welche in einem nachgeschalteten Verarbeitungsprozess die visuelle Detektionssensitivität beeinflussen. Somit konnte die vorliegende Arbeit ein thalamo-kortikales Netzwerk ermittelt werden, welches auf der Basis früher multisensorischer Integration zu einer Steigerung perzeptueller Sensitivität führt.
    Keywords Auditive Stimulation ; Auditory Stimulation ; Brain ; Cerebral Cortex ; Electroencephalography ; Elektroenzephalographie ; Functional Magnetic Resonance Imaging ; Funktionelle Magnetresonanztomographie ; Gehirn ; Großhirnrinde ; Sense Organs ; Sensorische Integration ; Sensory Integration ; Sinnesorgane ; Thalamus ; Visual Stimulation ; Visuelle Stimulation
    Language German
    Size 185 S.
    Publisher Universität, Fakultät für Naturwissenschaften
    Publishing place Magdeburg
    Document type Book ; Thesis
    Note Elektronische Publikation im Internet
    Database PSYNDEX

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  2. Book ; Online ; Thesis: Neuronale Prozesse auditorisch induzierter visueller Wahrnehmungssteigerung

    Tyll, Sascha [Verfasser]

    2010  

    Author's details von Sascha Tyll
    Keywords Medizin, Gesundheit ; Medicine, Health
    Subject code sg610
    Language German
    Document type Book ; Online ; Thesis
    Database Digital theses on the web

    Full text online

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  3. Article ; Online: Recent advances in neutral and anionic N-heterocyclic carbene – betaine interconversions. Synthesis, characterization, and applications

    Andreas Schmidt / Sascha Wiechmann / Tyll Freese

    ARKIVOC, Vol 2013, Iss 1, Pp 424-

    2013  Volume 469

    Keywords Organic chemistry ; QD241-441
    Language English
    Publishing date 2013-08-01T00:00:00Z
    Publisher Arkat USA, Inc.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

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  4. Article ; Online: Thalamic influences on multisensory integration.

    Tyll, Sascha / Budinger, Eike / Noesselt, Toemme

    Communicative & integrative biology

    2011  Volume 4, Issue 4, Page(s) 378–381

    Abstract: In everyday life our brain often receives information about events and objects in the real world via several sensory modalities, because natural objects often stimulate more than one sense. These different types of information are processed in our brain ... ...

    Abstract In everyday life our brain often receives information about events and objects in the real world via several sensory modalities, because natural objects often stimulate more than one sense. These different types of information are processed in our brain along different sensory-specific pathways, but are finally integrated into a unified percept. During the last years, studies provided compelling evidence that the neural basis of multisensory integration is not restricted to higher association areas of the cortex, but can already occur at low-level stages of sensory cortical processing and even in subcortical structures. In this article we will review the potential role of several thalamic structures in multisensory interplay and discuss their extensive anatomical connections with sensory-specific and multisensory cortical structures. We conclude that sensory-specific thalamic structures may act as a crucial processing node of multisensory interplay in addition to their traditional role as sensory relaying structure.
    Language English
    Publishing date 2011-07-01
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2451097-X
    ISSN 1942-0889 ; 1942-0889
    ISSN (online) 1942-0889
    ISSN 1942-0889
    DOI 10.4161/cib.4.4.15222
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Suzuki–Miyaura Cross-Coupling Reactions in Acetic Acid Employing Sydnone-Derived Catalyst Systems

    Lücke, Ana-Luiza / Wiechmann, Sascha / Freese, Tyll / Schmidt, Andreas

    Synlett

    2017  Volume 28, Issue 15, Page(s) 1990–1993

    Abstract: The catalyst system consisting of lithium N -phenylsydnone-4-carboxylate/Pd(PPh 3 4 has proven to be an effective catalyst for the Suzuki–Miyaura reaction of 2,4-dinitrochlorobenzene with boronic acids in acetic acid at pH 5.7, whereas the N - ... ...

    Abstract The catalyst system consisting of lithium N -phenylsydnone-4-carboxylate/Pd(PPh 3 4 has proven to be an effective catalyst for the Suzuki–Miyaura reaction of 2,4-dinitrochlorobenzene with boronic acids in acetic acid at pH 5.7, whereas the N -phenylsydnone carbene palladium complex [sydPd(PPh 3 2 Br] required pH 8.0.
    Keywords catalysis ; Suzuki–Miyaura reaction ; N-heterocyclic carbenes ; sydnones ; palladium ; pH value
    Language English
    Publishing date 2017-06-29
    Publisher © Georg Thieme Verlag
    Publishing place Stuttgart ; New York
    Document type Article
    ZDB-ID 2042012-2
    ISSN 1437-2096 ; 0936-5214
    ISSN (online) 1437-2096
    ISSN 0936-5214
    DOI 10.1055/s-0036-1589059
    Database Thieme publisher's database

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  6. Article: Palladium complexes of anionic N-heterocyclic carbenes derived from sydnones in catalysis

    Lücke, Ana-Luiza / Sascha Wiechmann / Tyll Freese / Zong Guan / Andreas Schmidt

    Zeitschrift für Naturforschung B. 2016 Apr. 1, v. 71, no. 6

    2016  

    Abstract: The anion of N-phenylsydnone, which can be generated on treatment of N-phenylsydnone with cyanomethyllithium without decomposition, can be represented as tripolar zwitterionic and as anionic N-heterocyclic carbene resonance forms. Its palladium complex ... ...

    Abstract The anion of N-phenylsydnone, which can be generated on treatment of N-phenylsydnone with cyanomethyllithium without decomposition, can be represented as tripolar zwitterionic and as anionic N-heterocyclic carbene resonance forms. Its palladium complex was prepared from 4-bromo-3-phenylsydnone and tetrakis(triphenylphosphine)palladium and proved to be active as catalyst in Suzuki-Miyaura reactions. Thus, 2,5-dibromo-3,4-dinitrothiophene was effectively converted into 2,5-diaryl-3,4-dinitrothiophenes with 1-naphthyl, (4-trifluoromethoxy)phenyl, [4-(methylsulfanyl)phenyl], and biphenyl-4-yl boronic acid. 3-(Phenanthren-9-yl)quinoline was prepared by Suzuki-Miyaura reaction starting from 3-bromoquinoline. 1-Chloro-2,4-dinitrobenzene cross-coupled with phenyl boronic acid, 1-naphthyl boronic acid, 9-phenanthryl boronic acid. 4-Bromobenzylic alcohol gave (4-isopropylphenyl)methanol on sydnone-palladium complex-catalyzed reaction with isopropyl boronic acid.
    Keywords Suzuki reaction ; alcohols ; carbenes ; catalysts ; catalytic activity ; palladium ; quinoline ; zwitterions
    Language English
    Dates of publication 2016-0401
    Size p. 643-650.
    Publishing place De Gruyter
    Document type Article
    ISSN 1865-7117
    DOI 10.1515/znb-2016-0006
    Database NAL-Catalogue (AGRICOLA)

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  7. Article ; Online: Audio-visual synchrony modulates the ventriloquist illusion and its neural/spatial representation in the auditory cortex.

    Bonath, Björn / Noesselt, Toemme / Krauel, Kerstin / Tyll, Sascha / Tempelmann, Claus / Hillyard, Steven A

    NeuroImage

    2014  Volume 98, Page(s) 425–434

    Abstract: An essential task of our perceptual systems is to bind together the distinctive features of single objects and events into unitary percepts, even when those features are registered in different sensory modalities. In cases where auditory and visual ... ...

    Abstract An essential task of our perceptual systems is to bind together the distinctive features of single objects and events into unitary percepts, even when those features are registered in different sensory modalities. In cases where auditory and visual inputs are spatially incongruent, they may still be perceived as belonging to a single event at the location of the visual stimulus - a phenomenon known as the 'ventriloquist illusion'. The present study examined how audio-visual temporal congruence influences the ventriloquist illusion and characterized its neural underpinnings with functional magnetic resonance imaging (fMRI). Behaviorally, the ventriloquist illusion was reduced for asynchronous versus synchronous audio-visual stimuli, in accordance with previous reports. Neural activity patterns associated with the ventriloquist effect were consistently observed in the planum temporale (PT), with a reduction in illusion-related fMRI-signals ipsilateral to visual stimulation for central sounds perceived peripherally and a contralateral increase in illusion-related fMRI-signals for peripheral sounds perceived centrally. Moreover, it was found that separate but adjacent regions within the PT were preferentially activated for ventriloquist illusions produced by synchronous and asynchronous audio-visual stimulation. We conclude that the left-right balance of neural activity in the PT represents the neural code that underlies the ventriloquist illusion, with greater activity in the cerebral hemisphere contralateral to the direction of the perceived shift of sound location.
    MeSH term(s) Acoustic Stimulation ; Adult ; Auditory Cortex/physiology ; Brain Mapping ; Female ; Humans ; Illusions/physiology ; Magnetic Resonance Imaging ; Male ; Photic Stimulation ; Sound Localization/physiology ; Visual Perception/physiology ; Young Adult
    Language English
    Publishing date 2014-09
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 1147767-2
    ISSN 1095-9572 ; 1053-8119
    ISSN (online) 1095-9572
    ISSN 1053-8119
    DOI 10.1016/j.neuroimage.2014.04.077
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    Zs.A 3664: Show issues Location:
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    Jg. 1995 - 2021: Lesesall (2.OG)
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  8. Article ; Online: Task-demands and audio-visual stimulus configurations modulate neural activity in the human thalamus.

    Bonath, Björn / Tyll, Sascha / Budinger, Eike / Krauel, Kerstin / Hopf, Jens-Max / Noesselt, Tömme

    NeuroImage

    2013  Volume 66, Page(s) 110–118

    Abstract: Recent electrophysiological studies have reported short latency modulations in cortical regions for multisensory stimuli, thereby suggesting a subcortical, possibly thalamic origin of these modulations. Concurrently, there is an ongoing debate, whether ... ...

    Abstract Recent electrophysiological studies have reported short latency modulations in cortical regions for multisensory stimuli, thereby suggesting a subcortical, possibly thalamic origin of these modulations. Concurrently, there is an ongoing debate, whether multisensory interplay reflects automatic, bottom-up driven processes or relies on top-down influences. Here, we dissociated the effects of task set and stimulus configurations on BOLD-signals in the human thalamus with event-related functional magnetic resonance imaging (fMRI). We orthogonally manipulated temporal and spatial congruency of audio-visual stimulus configurations, while subjects judged either their temporal or spatial congruency. Voxel-based fMRI results revealed increased fMRI-signals for the temporal versus spatial task in posterior and central thalamus, respectively. A more sensitive region of interest (ROI)-analysis confirmed that the posterior thalamic nuclei showed a preference for the temporal task and central thalamic nuclei for the spatial task. Moreover, the ROI-analysis also revealed enhanced fMRI-signals for spatially incongruent stimuli in the central thalamus. Together, our results demonstrate that both audio-visual stimulus configurations and task-related processing of spatial or temporal stimulus features selectively modulate thalamic processing and thus are in a position to influence cortical processing at an early stage.
    MeSH term(s) Adult ; Auditory Perception/physiology ; Brain Mapping ; Female ; Humans ; Magnetic Resonance Imaging/instrumentation ; Magnetic Resonance Imaging/methods ; Male ; Posterior Thalamic Nuclei/physiology ; Space Perception/physiology ; Thalamus/cytology ; Thalamus/physiology ; Time Perception/physiology ; Visual Perception/physiology ; Young Adult
    Language English
    Publishing date 2013-02-01
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1147767-2
    ISSN 1095-9572 ; 1053-8119
    ISSN (online) 1095-9572
    ISSN 1053-8119
    DOI 10.1016/j.neuroimage.2012.10.018
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Neural basis of multisensory looming signals.

    Tyll, Sascha / Bonath, Björn / Schoenfeld, Mircea Ariel / Heinze, Hans-Jochen / Ohl, Frank W / Noesselt, Tömme

    NeuroImage

    2013  Volume 65, Page(s) 13–22

    Abstract: Approaching or looming signals are often related to extremely relevant environmental events (e.g. threats or collisions) making these signals critical for survival. However, the neural network underlying multisensory looming processing is not yet fully ... ...

    Abstract Approaching or looming signals are often related to extremely relevant environmental events (e.g. threats or collisions) making these signals critical for survival. However, the neural network underlying multisensory looming processing is not yet fully understood. Using functional magnetic resonance imaging (fMRI) we identified the neural correlates of audiovisual looming processing in humans: audiovisual looming (vs. receding) signals enhance fMRI-responses in low-level visual and auditory areas plus multisensory cortex (superior temporal sulcus; plus parietal and frontal structures). When characterizing the fMRI-response profiles for multisensory looming stimuli, we found significant enhancements relative to the mean and maximum of unisensory responses in looming-sensitive visual and auditory cortex plus STS. Superadditive enhancements were observed in visual cortex. Subject-specific region-of-interest analyses further revealed superadditive response profiles within all sensory-specific looming-sensitive structures plus bilateral STS for audiovisual looming vs. summed unisensory looming conditions. Finally, we observed enhanced connectivity of bilateral STS with low-level visual areas in the context of looming processing. This enhanced coupling of STS with unisensory regions might potentially serve to enhance the salience of unisensory stimulus features and is accompanied by superadditive fMRI-responses. We suggest that this preference in neural signaling for looming stimuli effectively informs animals to avoid potential threats or collisions.
    MeSH term(s) Acoustic Stimulation ; Adult ; Auditory Perception/physiology ; Brain/physiology ; Brain Mapping ; Comprehension/physiology ; Female ; Humans ; Magnetic Resonance Imaging ; Male ; Photic Stimulation ; Reaction Time/physiology ; Visual Perception/physiology ; Young Adult
    Language English
    Publishing date 2013-01-15
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1147767-2
    ISSN 1095-9572 ; 1053-8119
    ISSN (online) 1095-9572
    ISSN 1053-8119
    DOI 10.1016/j.neuroimage.2012.09.056
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: Anionic N-heterocyclic carbenes by decarboxylation of sydnone-4-carboxylates

    Lücke, Ana-Luiza / Sascha Wiechmann / Tyll Freese / Martin Nieger / Tamás Földes / Imre Pápai / Mimoza Gjikaj / Arnold Adam / Andreas Schmidt

    Tetrahedron. 2018 Apr. 19, v. 74, no. 16

    2018  

    Abstract: Unstable N-heterocyclic carbenes can be masked and stabilized as pseudo-cross-conjugated hetarenium-carboxylates which decarboxylate on warming. This study deals with the decarboxylation of carboxylates of mesoionic compounds to generate anionic N- ... ...

    Abstract Unstable N-heterocyclic carbenes can be masked and stabilized as pseudo-cross-conjugated hetarenium-carboxylates which decarboxylate on warming. This study deals with the decarboxylation of carboxylates of mesoionic compounds to generate anionic N-heterocyclic carbenes. Lithium sydnone-4-carboxylates were therefore prepared via 4-bromosydnones by halogen-lithium exchange with nBuLi and subsequent treatment with carbon dioxide. Protonation gave the corresponding sydnone-4-carboxylic acids. Thermogravimetric measurements in addition to temperature dependent IR spectroscopy proved the decarboxylation of lithium sydnone-4-carboxylates and formation of the corresponding sydnone anions which can be represented as anionic N-heterocyclic carbenes. In DMSO-d6 solution, water favors the decarboxylation. Calculations have been performed to elucidate the mechanism of the decarboxylation in the absence and presence of water.
    Keywords anions ; carbenes ; carbon dioxide ; carboxylic acids ; chemical structure ; decarboxylation ; heterocyclic nitrogen compounds ; infrared spectroscopy ; lithium ; protonation ; temperature ; thermogravimetry
    Language English
    Dates of publication 2018-0419
    Size p. 2092-2099.
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 204285-x
    ISSN 1464-5416 ; 0040-4020 ; 0563-2064
    ISSN (online) 1464-5416
    ISSN 0040-4020 ; 0563-2064
    DOI 10.1016/j.tet.2018.03.019
    Database NAL-Catalogue (AGRICOLA)

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