Dissociating Semantic Integration and Inhibitory Control in the Remote Associates Test : A tDCS-EEG Study

Neuromodulation was utilized here to investigate the distinct involvement of two recognized cortical hubs for semantic integration (the left anterior temporal lobe, lATL) and inhibitory control (the right dorsolateral prefrontal cortex, rDLPFC) in creative problem-solving. Participants were presented with a list of category-exemplar words, selectively recalled some of them, and then solved a set of RAT problems. Selective retrieval was introduced to trigger inhibitory control over competitors. Critically, some RAT problems could be solved with words from the previous phases of the experiment, including words that might be less accessible due to inhibition. Other problems, however, could only be solved with unpresented words. Experiment 1 showed that anodal tDCS over the lATL had a negative effect on the production of correct responses to baseline RAT problems, but not on those that required inhibited solutions. Experiment 2 produced the reverse pattern with cathodal tDCS over the rDLPFC. Resting-state EEG recordings were obtained before and after delivering tDCS, which also revealed specific tDCS-induced changes in frequency bands depending on the site of stimulation. Overall, these findings provide support for the involvement of semantic and control processes in creative problem solving that are linked to different brain networks.