The impact of anodal tDCS on attentional networks as a function of trait anxiety and depressive symptoms: A preregistered double-blind sham-controlled experiment

Abstract

Attention is a multifaceted construct, including three distinct attentional networks: the alerting, orienting, and executive conflict networks. Recently, researchers have started to envision strategies to enhance the attentional networks, and transcranial Direct Current Stimulation (tDCS) has emerged as a promising tool to do so, especially regarding the executive conflict network. On the other hand, other research lines have suggested that anodal tDCS might yield more substantial impacts among depressive and anxious participants. In this preregistered study, we thus examined two questions. First, we wanted to replicate previous observations and tested whether anodal tDCS does improve the executive conflict network's efficiency. Second, we set out to clarify the impact of anxiety and depressive symptoms on this effect. To do so, we adopted a double-blind within-subject protocol in an unselected sample (n = 50) and delivered a single session of anodal— applied over the dorsolateral part of the left prefrontal cortex—versus sham tDCS during the completion of a task assessing the attentional networks. We assessed anxiety and depressive symptoms at baseline. Although there were no significant direct effects of tDCS on the attentional networks, we found that the higher the levels of depression and trait anxiety, the larger the executive conflict network's enhancement during tDCS. By highlighting the importance of trait anxiety and depression when considering the impact of tDCS on the attentional networks, this study fulfills a valuable niche in clinical neuroscience, wherein preclinical data provide critical clues for larger, more definitive future translational efforts.

Attentional Networks in Co-occurring Generalized Anxiety Disorder and Major Depression Disorder: Towards a Staging Approach to the Executive Control Deficits

“…As in previous research (e.g., Coussement et al, 2020;Lannoy et al, 2017;Maurage et al, 2017Maurage et al, , 2014, we first excluded data from trials with incorrect responses and RTs lower than 200 ms or greater than 2000 ms for each participant. Two subjects (one MDD/GAD and one HC) were excluded due to abnormaly elevated number of outliers and errors in their response pattern 1 .…”