Processing positive versus negative words : noninvasive brain stimulation effects on implicit affective regulation and state anxiety (Hebrew)

The present study aimed to examine the effects of anodal transcranial direct current stimulation (tDCS) over the right ventrolateral prefrontal cortex (rVLPFC), a brain region associated with emotion regulation, on the implicit emotional processing of positive and negative words, as well as on state anxiety levels. Participants were randomly assigned to either an experimental group receiving active tDCS or a control group receiving sham stimulation. Before and after the intervention, participants completed a lexical decision task (LDT) using words with negative and positive emotional-valence dimensions, alongside self-report anxiety questionnaires.

The study integrates use of rVLPFC-targeted non-invasive brain stimulation (tDCS) and a LDT to probe the implicit processing effects of emotional valence, and the impact of rVLPFC excitatory stimulation on accuracy and RTs during the task. The task was designed to examine processes related to reading, language processing, and emotional processing while utilizing advanced neuroscientific research tools.

The findings indicated that the intervention did not lead to significant improvements in lexical decision task performance, as measured by reaction times and accuracy. However, a significant reduction in state anxiety levels was observed only in the experimental group following active tDCS stimulation. In addition, a main effect of emotional valence was found, consistent with previous literature, whereby positive words were processed faster and more accurately than negative words.

These findings suggest that anodal tDCS over the right VLPFC may influence emotional regulation and anxiety-related processes, even in the absence of direct improvements in lexical decision task performance as a function of emotional valence. The study contributes to the understanding of the role of the rVLPFC in implicit emotional processing and highlights the potential relevance of non-invasive brain stimulation techniques for affecting emotional regulation and psychological well-being in adults, and should be further investigated in educational and neuro developmental populations.