Age-related modulations of alpha and gamma brain activities underlying anticipation and distraction.

Hesham A Elshafei,Olivier Bertrand,Lesly Fornoni,Aurélie Bidet-Caulet,Rémy Masson,Claude Alain

doi:10.1371/journal.pone.0229334

Abstract

Attention operates through top-down (TD) and bottom-up (BU) mechanisms. Recently, it has been shown that slow (alpha) frequencies index facilitatory and suppressive mechanisms of TD attention and faster (gamma) frequencies signal BU attentional capture. Ageing is characterized by increased behavioral distractibility, resulting from either a reduced efficiency of TD attention or an enhanced triggering of BU attention. However, only few studies have investigated the impact of ageing upon the oscillatory activities involved in TD and BU attention. MEG data were collected from 14 elderly and 14 matched young healthy human participants while performing the Competitive Attention Task. Elderly participants displayed (1) exacerbated behavioral distractibility, (2) altered TD suppressive mechanisms, indexed by a reduced alpha synchronization in task-irrelevant regions, (3) less prominent alpha peak-frequency differences between cortical regions, (4) a similar BU system activation indexed by gamma activity, and (5) a reduced activation of lateral prefrontal inhibitory control regions. These results show that the ageing-related increased distractibility is of TD origin.

Highlights

Imagine being in a game of bingo, waiting for the number to be called out, and suddenly your phone starts ringing
We investigated the impact of age and of cue-related top-down attention on alpha activity, at the individual alpha peak frequency, in the virtual regions of interest (ROIs)
In trials with distracting sounds, both groups displayed a similar reaction time (RT) pattern: in agreement with previous studies [35, 46 47], participants were faster after early distracting sounds and slower after late distracting sounds, than with no distractors. This pattern could be explained in light of the effects triggered by distracting sounds [review in 47,75]: (1) a persistent increase in arousal resulting in a RT reduction and (2) a strong transient attentional capture effect associated with a RT augmentation

Summary

Introduction

Imagine being in a game of bingo, waiting for the number to be called out, and suddenly your phone starts ringing In such situations, our brains rely on a balance between top-down (TD) anticipatory attentional mechanisms to better process upcoming (relevant) stimuli and bottom-up (BU) attentional capture that allows the processing and evaluation of distracting (irrelevant) stimuli [1]. Our brains rely on a balance between top-down (TD) anticipatory attentional mechanisms to better process upcoming (relevant) stimuli and bottom-up (BU) attentional capture that allows the processing and evaluation of distracting (irrelevant) stimuli [1] In this context, on one hand, TD attention promotes the processing of relevant stimuli through facilitatory and suppressive mechanisms, resulting in enhanced processing of relevant information and reduced brain responses to unattended inputs, respectively [review in 2–6].

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