Modulation Of Divergent And Convergent Thinking By Transcranial Direct Current Stimulation

Neural interventions via tDCS show encouraging potentials for modulating creative performance,but it is still unknown how tDCS affects divergent and convergent thinking differently.Divergent thinking and convergent thinking are core components of creativity.Behavioral and neuroimaging studies have revealed variations in the cognitive and neural mechanisms of these two forms of creative thinking.Therefore,different tDCS stimulation applied to the same brain region may have different modulatory effects on divergent and convergent thinking.The present study selectively manipulated two brain regions,the inferior frontal gyrus(IFG)and the dorsolateral prefrontal cortex(DLPFC),which are both strongly related to creative cognition.tDCS was used in two separate experiments to modulate the excitability of bilateral IFG and DLPFC in order to investigate the modulatory effects on divergent and convergent thinking.Study 1 found that cathodal stimulation over the left IFG and anodal stimulation over the right IFG(L-R+)increased originality of responses in divergent thinking and facilitated convergent thinking performance.Resting-state EEG results revealed a significant decrease of Alpha power in the frontal region.Anodal stimulation of the left IFG and cathodal stimulation of the right IFG(L+R-)improved only convergent thinking performance.Study 2 found that,compared with the sham stimulation,originality of divergent thinking was significantly enhanced in the L+Rcondition.Additionally,compared with the L-R+ group,flexibility scores were higher in the L+R-group.Resting-state EEG results revealed a significant reduction of Upper Alpha power in the left DLPFC of the L-R+ group.These results indicate that the different modulatory effects on top-down cognitive control and integration of semantic information,which caused by altered bilateral IFG and DLPFC excitability,may play different roles in the two types of creative cognition.Overall,the present study provides causal evidence for the differential involvement of IFG and DLPFC in divergent and convergent thinking and is important for further understanding of the cognitive and neural mechanisms underlying divergent and convergent thinking.