Voluntary direction of attention through alpha oscillations Electrophysiological signatures of adaptive and maladaptive attentional orientation

The electroencephalogram (EEG) is a recording of electrical activity of the brain. Certain patterns in the EEG can be related to specific cognitive operations. Neurons synchronize their activity when a sensory brain region is inactive, thereby producing rhythmic activity. These slow waves with a frequency of ~10 Hz are called alpha oscillations. Sensory information will be processed or ignored depending on the amount of alpha activity in brain regions associated with processing this information. Modulating alpha activity is thereby a mechanism to select important information for further processing. Resources for information processing can be allocated to specific sensory modalities, but also to select information based on location (spatial attention) or attributes such as color (feature-based attention). Even though the inhibitory influence of alpha activity is found to be pulsed, depending on the phase angle of the oscillation, experiments described in the current thesis do not support the hypothesis that information selection is also based on phase adjustment.