Attention-dependent suppression of distracter visual input can be cross-modally cued as indexed by anticipatory parieto-occipital alpha-band oscillations

Recent studies show that in addition to enhancing neural processing for att entionally relevant stimuli, selective attention also operates by suppressi ng the processing of distracter stimuli. When subjects are pre-cued to sele ctively deploy attention during voluntary (endogenous) attentional tasks, t hese mechanisms can be set up in advance of actual stimulus processing. Tha t is, the brain can be placed in a biased attentional state. Two recent cue ing studies have provided evidence for the deployment of such biased attent ional states [J.J. Foxe, G.V. Simpson, S.P. Ahlfors, Neuroreport 9 (1998) 3 929-3933; M.S. Worden, J.J. Foxe, N. Wang, G.V. Simpson, J. Neurosci. 20:RC 63 (2000) 1-6]. Specifically, these studies implicated oscillatory activity in the alpha frequency-band (8-14 Hz) as an anticipatory mechanism for sup pressing distracter visual stimulation. The current study extends these fin dings by showing that this alpha-suppressive effect is also invoked by cros s-modal cues. Auditory symbolic cues were used in an intermodal attention t ask, to direct subjects' attention to a subsequent task in either the visua l or auditory modality. Cueing attention to the auditory features of the im minent task stimuli resulted in significantly higher parieto-occipital alph a amplitude in the period preceding onset of this stimulus than when attent ion was cued to the visual features. Topographic mapping suggests that this effect is generated in regions of the inferior parietal cortex, areas that have been repeatedly implicated in the engagement and maintenance of visua l attention. Taken together, the results of this series of studies suggest that these parietal regions are capable of integrating sensory cues from mu ltiple sensory modalities in order to program the subsequent deployment of visual attention. (C) 2001 Elsevier Science B.V. All rights reserved.