[PS-3.4] Functional hemispheric asymmetry of the dorsolateral prefrontal cortex in statistical learningFunctional hemispheric asymmetry of the dorsolateral prefrontal cortex in statistical learning

Pesthy, O. ¹ , Horváth , K. ^{1, 2} , Török, C. . ^{1, 2} , Török, B. ³ , Janacsek, K. ^{1, 2} & Nemeth, D. . ^{1, 2}

1 ) Institute of Psychology, Eötvös Loránd University, Budapest, Hungary
2 MTA-ELTE NAP B Brain, Memory and Language Research Group, Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
3 Department of Cognitive Science, Budapest Institute of Technology and Economics, Budapest, Hungary

Procedural learning, the development of skills through extensive practice, is a crucial ability that facilitates processing of and automatic responses to complex environmental stimuli and predictive processing. Although many studies focused on procedural learning, different processes within procedural learning, and their neural underpinnings, are less characterized. Here we investigated two such processes: sequence learning and statistical learning. Previous studies highlighted the supporting role of the right dorsolateral prefrontal cortex (DLPFC) in statistical learning, while the role of the left DLPFC remained controversial. The goal of our study was to test, within the same experimental design, the involvement of the right and left DLPFC in statistical vs. sequence learning. Ninety healthy young adults participated in the study. Anodal transcranial direct current stimulation (tDCS) was applied over the right or left DLPFC while participants performed a cued version of a probabilistic sequence learning task in which statistical and sequence learning could be assessed in parallel. We found that anodal tDCS over the left DLPFC led to a weaker statistical learning performance compared to the right DLPFC and the sham (no stimulation) groups. We found no group differences in sequence learning performance. Our results are in line with previous findings highlighting an interhemispheric asymmetry in the role of the DLPFCs that may be specific to statistical but not sequence learning. These findings can contribute to a better understanding of the neurocognitive underpinnings of various sub-processes of procedural learning, such as statistical learning and sequence learning.
Keywords: Statistical learning, sequence learning, non-invasive brain stimulation