The Underlying Mechanism Of COMT Gene Val108/158Met Polymorphism Effects On Creative Thinking

Creativity is viewed as the driving force to the development of human civilization and plays a crucial role in the development of human society.It is basic requirement for us to improve creativity all over the nation to build an innovative country.Creativity refers to the individual’s ability to produce novel and practical ideas or products and divergent thinking has been proposed to be a key aspect of creativity.Torrance Tests of Creative Thinking(TTCT)is the most widely used tool to measure individual creativity,including three aspects: originality,fluency and flexibility.Generally speaking,the main reasons influencing the development and formation of individual creative thinking are heredity and environment.In some intelligence models,creativity and divergent thinking are facets of intelligence.Therefore,creativity should also have a strong genetic basis and should be – in a similar way as intelligence.Biological studies indicate dopamine(DA)projections to the forebrain are known to be involved in cognitive functioning and therefore can be assumed to be involved in creative thinking as well.Previous studies found catechol-O-methyltransferase(COMT)gene is one of the most important genes involving dopamine transmission and has been successfully related to prefrontal executive functioning encompassing cognitive processes like attention and working memory.COMT gene Val158 Met polymorphism refers to a single nucleotide polymorphism(SNP),a G → A transition in codon 158 of the COMT gene located at the q11 band of human chromosome 22,results in 3-to 4-fold difference in COMT enzyme activity by coding for the synthesis of the amino acid methionine(MET)instead of valine(VAL).Thus,individual with VAL/VAL genotype have a lower dopamine concentration in prefrontal cortex compared with the MET/MET genotype people.Several studies demonstrate COMT gene Val158 Met polymorphism is associated with creativity and best creative performance in carriers of the MET/MET genotype and worst performance in carriers with the VAL/VAL genotype.Of course,VAL/MET genotype have intermediate levels of creative performance.Now,conclusions on the relationship between COMT gene Val158 Met polymorphism and creativity are consistent,but the underlying mechanism on how different genotypes influence creative performance via brain is still unclear.On the other hand,with the appearance and development of Functional Magnetic Resonance Imaging(fMRI)technique,studies about the underlying mechanism of creativity focus on from cerebral hemisphere to specific structure and function in brain.A number of studies have confirmed both gray matter volume and resting-state functional connectivity(RSFC)in regions in default network(DMN)are related to divergent thinking,including medial prefrontal cortex(mPFC),medial temporal lobes(MTLs),bilateral inferior parietal lobule(IPL)and the posterior cingulate cortex(PCC).Meanwhile,several region in DMN showed significant activation in the processing of producing creative ideas.In conclusion,COMT gene Val158 Met polymorphism may affect creative performance by influence structure or function in DMN through adjust the concentration of dopamine in frontal cortex.Hence present study investigates this issue.First of all,our study explored how COMT gene Val158 Met polymorphism affected creative performance through brain by utilizing voxel-based morphometry(VBM)analysis and resting-state functional connectivity analysis.Then,we explored the activity in brain between different genotype groups when they performing creative task.Study 1 assessed individual creative performance by Torrance Tests of Creative Thinking.After controlling age,gender and intelligence,independent-samples T test on the structure image data showed there were no significant differences between the carriers with MET and the VAL/VAL genotype.RSFC analysis showed total creative score and original score were negatively correlated with the strength of RSFC between the mPFC and the left IPL in MET-carrier group.Meanwhile,total creative score and original score were positively correlated with the strength of RSFC between the mPFC and the left inferior frontal gyrus(IFG)in VAL/VAL group.Behavior analysis showed total creative score and original score were significantly higher in MET-carrier group compared with VAL/VAL group.Study 2 assessed individual creative performance by alternative uses task(AUT)and ordinary characteristics task(OCT),regarding different activation(AUT-OCT)as activity amplitude when individual performing creative tasks.After comparing the activity amplitude in two different groups,we found activity amplitude in right middle temporal gyrus(MTG)significantly higher in VAL/VAL group compared with MET-carrier group.In the meanwhile,AUT score was negatively correlated with the activity amplitude in right MTG in both MET-carrier group and VAL/VAL group.Behavior analysis showed there were no significant differences in AUT score in MET-carrier group and VAL/VAL group.In conclusion,we speculate the RSFC in DMN(mPFC and left IPL)can negatively predict creative behavior in Met-carrier group.Meanwhile,the RSFC between mPFC and left IFG can positively predict creative behavior in VAL/VAL group.Right MTG may involve in semantic processing such as semantic representation and control,conceptual integration and comprehension,and activating long-term memory.The stronger activity amplitude in MTG indicates the more active semantic processing and long-term memory extraction in the process of generating creative idea.