Baseline Differences in Anxiety Affect Attention and tDCS-Mediated Learning.

Benjamin C Gibson,Vincent P Clark,Teagan S Mullins,Alfred B Yu,Melissa Heinrich,Jeffrey T Hansberger

doi:10.3389/fnhum.2021.541369

Abstract

Variable responses to transcranial direct current stimulation (tDCS) protocols across individuals are widely reported, but the reasons behind this variation are unclear. This includes tDCS protocols meant to improve attention. Attentional control is impacted by top-down and bottom-up processes, and this relationship is affected by state characteristics such as anxiety. According to Attentional Control Theory, anxiety biases attention towards bottom-up and stimulus-driven processing. The goal of this study was to explore the extent to which differences in state anxiety and related measures affect visual attention and category learning, both with and without the influence of tDCS. Using discovery learning, participants were trained to classify pictures of European streets into two categories while receiving 30 min of 2.0 mA anodal, cathodal, or sham tDCS over the rVLPFC. The pictures were classifiable according to two separate rules, one stimulus and one hypothesis-driven. The Remote Associates Test (RAT), Profile of Mood States, and Attention Networks Task (ANT) were used to understand the effects of individual differences at baseline on subsequent tDCS-mediated learning. Multinomial logistic regression was fit to predict rule learning based on the baseline measures, with subjects classified according to whether they used the stimulus-driven or hypothesis-driven rule to classify the pictures. The overall model showed a classification accuracy of 74.1%. The type of tDCS stimulation applied, attentional orienting score, and self-reported mood were significant predictors of different categories of rule learning. These results indicate that anxiety can influence the quality of subjects’ attention at the onset of the task and that these attentional differences can influence tDCS-mediated category learning during the rapid assessment of visual scenes. These findings have implications for understanding the complex interactions that give rise to the variability in response to tDCS.

Highlights

Attentional control is assumed to occur through bottomup, implicit processes and top-down, consciously instigated processes, with this distinction codified via behavioral (Jonides, 1981; Wolfe et al, 1989) and neuroscience measures (Desimone and Duncan, 1995; Corbetta and Shulman, 2002; Mazaheri et al, 2011)
The results of this study support the interpretation that anodal transcranial direct current stimulation (tDCS) over the right ventrolateral prefrontal cortex (rVLPFC) is associated with an increased ability to learn rule 1, which requires an insight regarding the importance of traffic direction (Gibson et al, 2020)
As predicted by Attentional Control Theory, the attention differences captured by the orienting subscale might themselves be the result of differences in state anxiety

Summary

Introduction

Attentional control is assumed to occur through bottomup, implicit processes and top-down, consciously instigated processes, with this distinction codified via behavioral (Jonides, 1981; Wolfe et al, 1989) and neuroscience measures (Desimone and Duncan, 1995; Corbetta and Shulman, 2002; Mazaheri et al, 2011). Attentional Control Theory provides an account of how anxiety impacts attention and negatively impacts higher-level cognitive processing (Eysenck et al, 2007). This theory proposes that there are two competing systems of attention; a purpose-driven, top-down system, and a stimulus-driven, bottom-up system. Anxiety alters the balance of these competing systems in favor of bottom-up processing (Derryberry and Reed, 2002; Eysenck et al, 2007) This dichotomy is supported by neuroimaging, which has found partially overlapping substrates for these two systems (Corbetta and Shulman, 2002; Corbetta et al, 2008)

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