The processing and resolution of conflicts are impossible without cognitive control, and the transferability of advanced cognitive functions is an evolutionary mechanism of human being to adapt to the rapidly changing environment. It is generally believed that cognitive control plays a general role in the processing of different conflicts. However, many studies have found that different conflicts show specific and modularized mechanisms. Some studies even found that cognitive control has obvious boundaries, such as dimension-overlap type (hereafter type for short). The generality and specificity of cognitive control requires to be further discussed.
In this thesis, I examined the similarities and difference of the cognitive control mechanisms between different conflicts, and the neural bases that generate the mechanism differences. Based on the logical perspectives of parallel comparison, transferability, and correlation etc., I examined control mechanisms of different conflict types and sensory modalities. A meta-analysis was conducted in Study 1 by summarizing a large number of currently accumulated imaging studies on conflict processing, and the results showed both general and specific brain areas for different conflict types. In Studies 2, fMRI method was applied to empirically investigate the similarities and differences in the mechanisms between conflicts of different types. With general linear model (GLM) analyses, significant specificity of brain activation in different conflicts types was found. Moreover, multivariate pattern analysis (MVPA) method was applied to reveal that many brain regions are involved in the processing of both conflict types, but mutual predictions cannot be made between conflicts of different types, which may explain the boundary of conflict adaptation to some extent. In Study 3, I examined the conflict adaptation effect between different sensory modalities, and found that the sensory modality is also a boundary of cognitive control, which expanded the current understanding of modularization of cognitive control. In Study 4, similar results as Study 2 were found in an fMRI experiment of visual and auditory conflicts. In addition, both fMRI studies showed that the activation or inhibition of the default network and dorsal attention network is involved in the generation and disappearance of conflict adaptation.
By integrating meta-analytical, behavioral and brain imaging studies, the current studies draw consistent conclusions based on different logical perspectives: (1) The sensory channel is a boundary of the conflict adaptation effect; (2) The processing mechanisms of different conflicts show more of specificity than generality; (3) Different conflicts have finer differences in brain activation intensity and spatial patterns; (4) Activation or inhibition of default network and dorsal attention network may play an important role in the occurrence or disappearance of conflict adaptation.