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Modulation of EEG-Alpha oscillations during visual spatial attention

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Defense Thèse de doctorat : Univ. Genève et Lausanne, 2008 - Neur. 28 - 2008/09/26
Abstract Voluntarily directing visual attention to a cued position in space leads to improved processing of forthcoming visual stimuli at this position, due to anticipatory tuning of visual cortex activity. Recent evidence points to a determining role of modulations of posterior alpha-band activity (8-14Hz) during attention orienting.This thesis investigates the modulation of EEG alpha-oscillations during anticipatory preparation for a visual target. The results show that the topography of alpha band power maps is found to correspond to a retinotopic organisation according to the direction of attention in the time prior to the expected target arrival. Moreover, the thesis presents evidence for a dynamic modulation of alpha amplitudes according to task demands by showing that both alpha power decreases and increases can occur at different times in the course of anticipation of a visual target stimulus. The findings presented here provide further support for an active facilitative versus inhibitory role of alpha-power decreases and increases during attention orienting, by showing retionotopic specificity and dynamic deployment of attentional resources to prepare versus maintain the cortex for optimal target processing.
Keywords Alpha frequency bandEEG map topographyOscillatory brain activityRetinotopyVisual spatial attentionTranscranial magnetic stimulationVisual cortex excitability
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URN: urn:nbn:ch:unige-401093
Note Thèse en Neurosciences des universités de Genève et de Lausanne
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RIHS, Tonia. Modulation of EEG-Alpha oscillations during visual spatial attention. Université de Genève. Thèse, 2008. https://archive-ouverte.unige.ch/unige:40109

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Deposited on : 2014-09-10

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