Neural mechanisms of feature-based attention in early visual cortex of the human brain

25 June 2013
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In a series of experiments we investigated neural mechanisms and
dynamics of feature-based sustained visual attention in the human brain
by means of EEG recordings. With our unique technique to frequency-tag
individual stimuli at different frequencies, we can investigate neural
dynamics and competitive interactions of facilitation and suppression
and the underlying time courses in multi-element stimulus displays. By
analyzing the steady state visual evoked potential (SSVEP) – an ongoing
oscillatory neural signal that has the same frequency as the respective
driving stimulus - we were able to provide experimental evidence for
central predictions of the feature similarity gain model. Furthermore,
we demonstrated significantly different time courses of facilitation and
suppression in non-spatial feature-based attentional cued shifts to a
certain color questioning the idea of one strictly limited resource that
guides visual processing. In one of our most recent experiments we
showed that global feature-based facilitation is mandatory, even when it
conflicts with task demands.