| Popis: |
Implicit associations can interfere with cognitive operations and behavioural decisions without direct intention. Enhancement of neural activity with anodal transcranial direct current stimulation (tDCS) was proposed to reduce implicit associations by means of improved cognitive control. However, the notion of a direct inhibition of implicit associations by cathodal tDCS has not yet been addressed. Here, we introduce a cathodal tDCS configuration with extracephalic return electrode to reduce implicit associations. Based on previous studies on implicit spatial-numerical associations, we generalize the stimulation rationale by demonstrating efficacy in the standardized implicit association task (IAT). In this double-classification task, insect vs. flower pictures and negative vs. positive words are mapped together onto two shared response keys with crossed response assignments in separate blocks. Responses were faster when insect + negative and flower + positive stimuli required the same answer (IAT effect). Most critically, the IAT effect was reduced during 1 mA prefrontal cathodal tDCS as compared to sham stimulation. Results are consistent with the proposed stimulation rationale, with our previous observations, and complementary to previous attempts to modulate IAT effects with (medial) prefrontal anodal tDCS configurations. Limited by the validity of the IAT in general, results suggest transferability to other implicit biases. |
