RT Journal Article SR Electronic T1 Transcranial Direct Current Stimulation Facilitates Decision Making in a Probabilistic Guessing Task JF The Journal of Neuroscience JO J. Neurosci. FD Society for Neuroscience SP 4241 OP 4245 DO 10.1523/JNEUROSCI.2924-09.2010 VO 30 IS 12 A1 David Hecht A1 Vincent Walsh A1 Michal Lavidor YR 2010 UL http://www.jneurosci.org/content/30/12/4241.abstract AB In a random sequence of binary events where one alternative occurs more often than the other, humans tend to guess which of the two alternatives will occur next by trying to match the frequencies of previous occurrences. Based on split-brain and unilaterally damaged patients' performances, it has been proposed that the left hemisphere (LH) tends to match the frequencies, while the right hemisphere (RH) tends toward maximizing and always choosing the most frequent alternative. The current study used transcranial direct current stimulation (tDCS) to test this hemispheric asymmetry hypothesis by stimulating the dorsolateral prefrontal cortex of each hemisphere and simultaneously inhibiting the corresponding region in the homotopic hemisphere, while participants were engaged in a probabilistic guessing task. Results showed no difference in strategy between the three groups (RH anodal/LH cathodal, LH anodal/RH cathodal, no stimulation) as participants predominantly matched the frequencies of the two alternatives. However, when anodal tDCS was applied to the LH and cathodal tDCS applied to the RH, participants became quicker to select the most frequent alternative. This finding is in line with previous evidence on the involvement of the LH in probabilistic learning and reasoning and adds to a number of demonstrations of anodal tDCS leading to some behavioral enhancement or change in bias.