Intra-modal and cross-modal spatial attention to auditory and visual stimuli. An event-related brain potential study.
This study investigated cross-modal interactions in spatial attention by means of recording event-related brain potentials (ERPs). Noise bursts and light flashes were presented in random order to both left and right field locations separated by 60 degrees in free-field. One group of subjects was instructed to attend selectively to the noise bursts (attend-auditory group), and a second group attended only to the flashes (attend-visual group). On different runs attention was directed to either the right or left field stimuli of the designated modality. In the attend-auditory group, noise bursts at the attended location elicited a broad, biphasic negativity (Nd) beginning at 70 ms. The cross-modal spatial attention effect on the auditory ERPs in the attend-visual group was very similar in morphology, but the Nd was reduced in amplitude relative to the intra-modal effect. In the attend-visual group, flashes at the attended location elicited enhanced early (100-200 ms) and late (200-350 ms) ERP components relative to unattended-location flashes. The cross-modal effect in the attend-auditory group included small but significant enhancements of early components of the visual ERPs. It was concluded that spatial attention has a multi-modal organization such that the processing of stimuli at attended locations is facilitated at an early, sensory level, even for stimuli of an unattended modality.
Teder-Sälejärvi
W A
WA
Department of Neurosciences 0608, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0608, USA. wat@sepd1.ucsd.edu
Münte
T F
TF
Sperlich
F
F
Hillyard
S A
SA
D000161:Acoustic Stimulation; D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D013037:Spatial Behavior / Q000502:physiology*