Effects of Auditory Stimuli in the Horizontal Plane on Audiovisual Integration: An Event-Related Potential Study

Abstract

This article aims to investigate whether auditory stimuli in the horizontal plane, particularly originating from behind the participant, affect audiovisual integration by using behavioral and event-related potential (ERP) measurements. In this study, visual stimuli were presented directly in front of the participants, auditory stimuli were presented at one location in an equidistant horizontal plane at the front (0°, the fixation point), right (90°), back (180°), or left (270°) of the participants, and audiovisual stimuli that include both visual stimuli and auditory stimuli originating from one of the four locations were simultaneously presented. These stimuli were presented randomly with equal probability; during this time, participants were asked to attend to the visual stimulus and respond promptly only to visual target stimuli (a unimodal visual target stimulus and the visual target of the audiovisual stimulus). A significant facilitation of reaction times and hit rates was obtained following audiovisual stimulation, irrespective of whether the auditory stimuli were presented in the front or back of the participant. However, no significant interactions were found between visual stimuli and auditory stimuli from the right or left. Two main ERP components related to audiovisual integration were found: first, auditory stimuli from the front location produced an ERP reaction over the right temporal area and right occipital area at approximately 160–200 milliseconds; second, auditory stimuli from the back produced a reaction over the parietal and occipital areas at approximately 360–400 milliseconds. Our results confirmed that audiovisual integration was also elicited, even though auditory stimuli were presented behind the participant, but no integration occurred when auditory stimuli were presented in the right or left spaces, suggesting that the human brain might be particularly sensitive to information received from behind than both sides.

Effects of ipsilateral and bilateral auditory stimuli on audiovisual integration

“…The initial difference between AV and A + V was observed at 180-200 ms over the parietal-occipital areas with ipsilateral auditory stimuli, which was consistent with previous studies [9,15]. However, the latency of the ERP activity in the current study was slightly delayed compared with that reported in a previous study [15].…”

“…In contrast, when the visual and auditory stimuli were presented in different locations, little or no enhancement was observed [2,[4][5][6]. Some studies have investigated the effect of unilateral [9] or bilateral auditory stimuli [10] on AV integration with central presentation of visual stimuli and found that significant AV integration is induced by bilateral auditory stimuli rather than by unilateral auditory stimuli [9,10]. Some studies have investigated the effect of unilateral [9] or bilateral auditory stimuli [10] on AV integration with central presentation of visual stimuli and found that significant AV integration is induced by bilateral auditory stimuli rather than by unilateral auditory stimuli [9,10].…”

The temporal reliability of sound modulates visual detection: An event-related potential study

“…2c). Some studies of AV integration reported a similar ERP component in right temporal area but not in left temporal area [15,22]. They hypothesized that the ERP component in the right temporal area is related to AV interaction that originates in the anterior part of the right temporal lobe and/or the inferior lateral prefrontal cortex.…”

Event-Related Potentials Extraction of Working Memory Using Wavelet Algorithm

“…Event related potentials are initiated by neuronal mass activity that can generate measurable electric scalp fields in fixed-time relation to an event to find a similar effects of inversion and contrast reversal behaviorally on reflecting various stimuli (Yang et al, 2013). Analyzing the ERPs can serve cognitive purposes in assessing cognitive responses without recognizable performances, but with neurophysiologic activity recorded.…”