Neural mechanisms of intermodal sustained selective attention with concurrently presented auditory and visual stimuli

Katja Saupe

doi:10.3389/neuro.09.058.2009

Abstract

We investigated intermodal attention effects on the auditory steady-state response (ASSR) and the steady-state visual evoked potential (SSVEP). For this purpose, 40-Hz amplitude-modulated tones and a stream of flickering (7.5 Hz) random letters were presented concurrently. By means of an auditory or visual target detection task, participants’ attention was directed to the respective modality for several seconds. Attention to the auditory stream led to a significant enhancement of the ASSR compared to when the visual stream was attended. This attentional modulation was located mainly in the right superior temporal gyrus. Vice versa, attention to the visual stream especially increased the second harmonic response of the SSVEP. This modulation was focused in the inferior occipital and lateral occipitotemporal gyrus of both hemispheres. To the best of our knowledge, this is the first demonstration of amplitude modulation of the ASSR and the SSVEP by intermodal sustained attention. Our results open a new avenue of research to understand the basic neural mechanisms of intermodal attention in the human brain.

Highlights

Everyday life in a complex multisensory environment requires shielding the perceptual system from overflow
We investigated intermodal attention effects on the auditory steady-state response (ASSR) and the steady-state visual evoked potential (SSVEP)
Attention to the visual stream especially increased the second harmonic response of the SSVEP.This modulation was focused in the inferior occipital and lateral occipitotemporal gyrus of both hemispheres.To the best of our knowledge, this is the first demonstration of amplitude modulation of the ASSR and the SSVEP by intermodal sustained attention

Summary

Introduction

Everyday life in a complex multisensory environment requires shielding the perceptual system from overflow. Similar to intramodal attention (Hillyard et al, 1973; Hansen and Hillyard, 1980, 1984; Näätänen, 1992; Alho et al, 1994a,b; Arnott and Alain, 2002), selective intermodal attention leads to a frontocentrally distributed enhanced negativity in the ERP, elicited by sounds when the auditory modality was attended compared to when the visual (Woods et al, 1992; Alho et al, 1994b; Eimer and Schröger, 1998; Talsma and Kok, 2001, 2002) or the somatosensory (Hötting et al, 2003) modality had to be attended. In the visual modality intermodal attention leads to an enhanced negativity in the ERP (elicited by the relevant visual stimulus) at posterior electrodes when the visual modality was attended compared to when the auditory modality was attended (Woods et al, 1992; Eimer and Schröger, 1998)

Methods

Results

Discussion

Conclusion