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| Gamma-Aktivität und vaskuläre Antwort im visuellen Kortex des Menschen Werner, Peter |
| Main title | Gamma-Aktivität und vaskuläre Antwort im visuellen Kortex des Menschen |
| Subtitle | Einfluss von Kontrast und Aufmerksamkeit |
| Title variations | Influence of stimulus-contrast and attentive state on gammaband activity and vascular response in the human visual cortex |
| Author(s) | Werner, Peter
Place of birth: Leipzig |
| 1. Referee | Priv.-Doz. Dr. med. H. Obrig |
| Further Referee(s) | Prof. Dr. A. J. Fallgatter Priv.-Doz. Dr. med. M. L. Schroeter |
| Keywords | Gamma EEG, Nirs-fMRT |
| Classification (DDC) | 610 Medical sciences; Medicine |
| Summary | A prompt behavioral response to a stimulus depends both on the salience of the stimulus as well as the subject's preparedness. Thus, both stimulus properties and cognitive factors, such as attention, may determine the strength of neuronal synchronization in the gamma range. For a comprehensive investigation of stimulus-response processing through noninvasive imaging, it is, however, a crucial issue whether both kinds of gamma modulation elicit a hemodynamic response. Here, we show that, in the human visual cortex, stimulus strength and internal state modulate sustained gamma activity and hemodynamic response in close correspondence. When participants reported velocity changes of gratings varying in contrast, gamma activity (35-70 Hz) increased systematically with contrast. For stimuli of constant contrast, the amplitude of gamma activity before the behaviorally relevant velocity change was inversely correlated to the behavioral response latency. This indicates that gamma activity also reflects an overall attentive state. For both sources of variance, gamma activity was tightly coupled to the hemodynamic response measured through optical topography. Because of the close relationship between high-frequency neuronal activity and the hemodynamic signal, we conclude that both stimulus-induced and state-dependent gamma activity trigger a metabolic demand and are amenable to vascular-based imaging. |
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| Number of pages | 71 |
| FU Department | Department of Medicine - Charité - University Medicine Berlin |
| Year of publication | 2010 |
| Document type | Doctoral thesis |
| Media type/Format | Text |
| Language | German |
| Terms of use/Rights | Nutzungsbedingungen |
| Date of defense | 2010-09-03 |
| Created at | 2010-07-15 : 10:28:15 |
| Last changed | 2010-08-03 : 10:21:28 |
| Static URL | http://www.diss.fu-berlin.de/diss/receive/FUDISS_thesis_000000018209 |
| NBN | urn:nbn:de:kobv:188-fudissthesis000000018209-6 |
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