Age-Related Shifts in Theta Oscillatory Activity During Audio-Visual Integration Regardless of Visual Attentional Load.

Yanna Ren,Shengnan Li,Tao Wang,Weiping Yang

doi:10.3389/fnagi.2020.571950

Abstract

Audio-visual integration (AVI) is higher in attended conditions than in unattended conditions. Here, we explore the AVI effect when the attentional recourse is competed by additional visual distractors, and its aging effect using single- and dual-tasks. The results showed the highest AVI effect under single-task-attentional-load condition than under no- and dual-task-attentional-load conditions (all P < 0.05) in both older and younger groups, but the AVI effect was weaker and delayed for older adults compared to younger adults for all attentional-load conditions (all P < 0.05). The non-phase-locked oscillation for AVI analysis illustrated the highest theta and alpha oscillatory activity for single-task-attentional-load condition than for no- and dual-task-attentional-load conditions, and the AVI oscillatory activity mainly occurred in the Cz, CP1 and Oz of older adults but in the Fz, FC1, and Cz of younger adults. The AVI effect was significantly negatively correlated with FC1 (r2 = 0.1468, P = 0.05) and Cz (r2 = 0.1447, P = 0.048) theta activity and with Fz (r2 = 0.1557, P = 0.043), FC1 (r2 = 0.1042, P = 0.008), and Cz (r2 = 0.0897, P = 0.010) alpha activity for older adults but not for younger adults in dual task. These results suggested a reduction in AVI ability for peripheral stimuli and a shift in AVI oscillation from anterior to posterior regions in older adults as an adaptive mechanism.

Highlights

Individuals are often inundated with stimuli from various sensory modalities (Xu et al, 2020)
The results showed that Audio-visual integration (AVI) occurred for all conditions, and it was greatest for the single-task-attentional-load condition in both older and younger adults (Figures 3B–D), indicating that AVI was greatly influenced by attentional load, and the modulation of attentional load on AVI effect was different between singleand dual-tasks
The results showed that the highest AVI effect was found for the single-taskattentional-load condition in both older and younger adults, and the AVI was weaker and delayed in older adults

Summary

Introduction

Individuals are often inundated with stimuli from various sensory modalities (e.g., auditory, visual, olfactory, and somatosensory stimuli) (Xu et al, 2020). The individual knows it is a speeding train, and is even able to estimate its speed. The process merging information from different modalities is called multisensory integration (Spence, 2011; Stein, 2012). Most people perceive the outside world by relying more on visual information and auditory information, and the procedure merging information from auditory and visual modalities is called audio-visual integration (AVI) (Meredith et al, 1987; Stein and Meredith, 1993; Laurienti et al, 2006). The AVI assists us to accurately perceive the outside world, and these

Methods

Results

Conclusion