Janacsek, K. 1, 2 , Ambrus, G. G. 3 , Paulus, W. 4 , Antal, A. 4 & Nemeth, D. 1, 2
1 Brain, Memory and Language Lab, Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
2 Institute of Psychology, Eötvös Loránd University, Budapest, Hungary
3 Department of Psychology, Friedrich Schiller University, Jena, Germany
4 Georg-August University of Göttingen, Department of Clinical Neurophysiology, Göttingen, Germany
Picking up statistical regularities of patterns from the environment is essential for predictive and adaptive behavior. One of the most important challenges is to understand how statistical learning occurs and how the acquired information consolidates and stabilizes in the brain. Evidence suggests that the prefrontal cortex (PFC) has a critical role in these processes; the division of labor between hemispheres, however, is less characterized. The aim of the present study was to directly investigate the role of the right and left PFC in implicit statistical learning and its consolidation. Healthy, young adults were trained on a probabilistic sequence learning task. Anodal transcranial direct current stimulation (tDCS) over the left or right dorsolateral PFC was applied during the training in order to modify learning-related cortical plasticity in the targeted brain regions by increasing neural excitability. Performance was retested after a 2-hour stabilization period and a 24-hour retention period. We found a trend for higher engagement of the right PFC leading to enhanced statistical learning. In contrast, higher engagement of the left PFC induced by the anodal tDCS led to a weaker performance in the retention phase suggesting disturbed consolidation. These results highlight an interhemispheric competition between the underlying memory systems.