Using transcranial Direct Current Stimulation (tDCS) to influence decision criterion in a target detection paradigm

Abstract

In this paper we investigate how a psychological theory used to model perceptual learning and face recognition, can be used to predict that anodal tDCS delivered over the DLPFC at Fp3 site (for 10 mins duration at 1.5mA intensity) modulates the decision criterion, C, (and not d-prime, d') in a target detection task. In two between-subjects and double-blind experiments (n=112) we examined the tDCS effects on C when subjects were engaged in a target detection task, in the first instance involving artificial checkerboard stimuli (Experiment 1a), and subsequently face stimuli (Experiment 1b). The results from both experiments revealed that in the sham/control groups a significantly higher C was used when detecting a target pattern (Experiment 1a) or face (Experiment 1b) presented on a familiar rather than a random background. Importantly, anodal tDCS significantly reduced/reversed this difference between C adopted for familiar and random backgrounds in both Experiment 1a and 1b without affecting d'. These results contribute to advance our understanding of the tDCS-induced effects on stimulus representation and to the literature regarding the modulation of C