Figure 1.

Word learning paradigm. (A) Participants were shown a photographic illustration depicting an action/object paired with a spoken pseudoword. They had to decide intuitively if the presented coupling was a correct or incorrect match. Two-hundred milliseconds after onset of the sound, the picture appeared. Responses had to be given within a time window of 3000 ms. The interstimulus interval (ISI) was 2000 ms between two trials. (B) One learning session consisted of 680 single trials, subdivided into five blocks with a 2 min break. Each pseudoword was shown 10 times with the “correct” action/object (depicted by two different images) as well as 10 times with different “incorrect” images. (C) Study design: prior to the first learning session participants were screened with a neuropsychological test battery (NP) and were introduced to the learning paradigm with a small lexical pre-test (PT) consisting of five words. Each participant completed three learning sessions on three different days with three different lexicon sets. During the task, participants received anodal, cathodal or sham tDCS in a randomized order across learning sessions (1 mA for 20 min; double blind application). At the start of each session the stimulation side over the left motor cortex (MC) was localized using transcranial magnetic stimulation (TMS). tDCS stimulation and the learning paradigm started simultaneously, the latter exceeding the stimulation for approximately 20 min. After each session, patients were asked to translate the acquired pseudowords into notions of their native language (T). Abbreviations: NP, neuropsychological testing; PT, pre-test; T, translation test.