ERP Research On The Abstract Representation At Different Hierarchies

Previous studies found that the function of different areas of the cerebral cortex is not the same.Although currently do not know how the whole brain cortex cognitive processing,studies have found that the frontal cortex has regularity in terms of cognitive processing abstract.Lashley(1951)first noted that behavior displays hierarchical structure,comprising nested subroutines.Later Koechlin and Summerfield(2007)proposed one influential hypothesis is that the anterior-toposterior axis of the PFC is organized hierarchically enroute to action.In recent ten years,only a limited amount of literature examines the characterization of abstract hierarchical levels related brain cortex.However,these studies did not address how abstract representation at different hierarchies unfolds in time,and the characteristic of dynamic activation of brain areas is still unclear.In order to study the dynamic process of abstract representation,it is necessary to use the ERP method that is prominent in time resolution.Based on this,we designed different abstract representation tasks at different hierarchies,two experiments as followed are included in this research:Experiment 1 mainly examined cognitive neural mechanism composed of numbers and letters with abstract representation at different hierarchies.Participants were required to make the target and non-target response to abstract task,in order to investigate ERP waveform,ERP component,time course of cortical activation and distribution of the entire active region in abstract representation task at different hierarchies.The results suggested that the higher hierarchy of the target,the higher uncertainty in decision,the greater N2 was evoked;on the contrary,the lower hierarchy of the target,the more specific,the smaller N2 was elicited.In addition,there was different cognitive background updating at the different hierarchies,the lower the more specific context cues,the more thorough cognitive updating.Conversely,the higher the more abstract,the more couldn't be completely updated,especially the higher target,resulted in could not to make reliable decisions due to more uncertainty.Therefore the cognitive background couldn't be updated,so the P3 amplitude of the high target was the smallest.Experiment 2 mainly examined cognitive neural mechanism composed of numbers with relational integration abstract representation task.Participants were required to make the corresponding response to relational integration task at different hierarchies,in order to investigate cognitive neural mechanism in relational integration abstract representation task,build neural mechanisms model and distinguish the difference between policy abstraction andrelational integration abstraction.The results showed that: compared with the lower relationship types,the P2 amplitude was larger in higher relationship types,may be reflect the greater intensity of perceptual encoding;compared with the higher relationship types,the low relationship types evoked the N2 amplitude was more negative,which may reflects the continuation of cognitive processing on the basis of P2,the higher relationship reduced the cognitive load processing needs while the low relationship enhanced.In addition,the higher relationship elicited larger P3 than the lower relationship,suggested that the different results evaluation and background updating.Taken together,these results of this paper showed that:(1)Both the policy abstraction and relational integration elicited N2 and P3 waves,may indicate different cognitive processing mechanisms.The N2 component of the experiment 1may reflect decision certainty and uncertainty,the P3 component may reflect cognitive background updating;the N2 component of the experiment 2 may reflects the continuation of cognitive processing on the basis of P2,P3 component may imply different results evaluation and background updating.(2)Compared with the policy abstraction,the relational integration elicited the P2 wave,significant differences in the P2 amplitude may reflect the perceptual coding at different intensities.(3)The policy abstraction showed significant type difference,while no significant difference in the relational integration,the difference may reflect different psychological mechanisms and cognitive processing mechanisms.(4)Activation of the cerebral cortex area confirmed: the more abstract cognitive processing,the more rostral regions of the PFC.It may be more appropriate affirmative task paradigm,the future needed more research further support.(5)The policy abstraction and the relational integration abstraction may reflect different processing mechanisms model.