Figure 1.

The training paradigm and the tasks used. A, Participants in the parietal or motor tRNS + Training and in the Training Only groups were trained intensively (560 trials per day) on a numerosity discrimination task for 5 consecutive days, i.e., day 2–6 while (B) receiving real or sham stimulation to the parietal or motor areas. Participants on the Stimulation Only group received no training. Before the training (day 1, pretraining), all participants were tested with (C) the numerosity discrimination task in addition to other continuous quantity-based tasks (time and space discrimination), arithmetic and control tasks. The same cognitive tasks were repeated at the end of the training (day 7, post-training) to test for any training-induced change, and (D) in the parietal tRNS + Training and Training Only groups again at week 4, 8, 12, and 16 post-training to test for any long-term effect of the training.