Task-modulated Hemispheric Asymmetry Of Cognitive Control

Cognitive control is such a psychological process or ability which is guided by targets and making appropriate behavioral responses to achieve the intended purpose through eliminating interferences or resolving conflicts. It is a cognitive processing which contains regulation, control and management of cognitive processes. The previous researches about the brain lateralization of cognitive control were limited at the behavior level, while the brain mechanisms of laterality were lack of attention. There is a gap between the underlie brain mechanisms of lateralization and the discoveries by of former behavioral studies. It is therefore necessary to examine the neural processing mechanisms of cognitive control laterality in our brain imaging study.In Experiment1, we used the task state fMRI technology to explore the existence of brain lateralization in the Stroop task. Through the slow event-related design used in this experiment the influence of conflict adaptation can be eliminated. Our results of Stroop effects repeated the findings of classic Stroop task studies in both the behavior and brain activation results; and cognitive control laterality was mainly found in the left hemispheric cognitive control brain regions; the lateralization time series analysis also suggested that the left hemisphere played a leading role in the cognitive control.In Experimental2, the resting state fMRI was performed to illustrate the brain lateralization of cognitive control and explore the differences of cognitive control processing laterality between the spontaneous brain activity and its activations in the task state. It was found that comparing to the control group accepted the conflict-free trials, the experimental group which received the Stroop conflict task had significant spontaneous activations in the brain regions of typical cognitive control brain regions as well as the inferior precentral gyrus, suggesting that there exists spontaneously brain activities which were modulated by the cognitive control processing. Besides, the cognitive control-related brain lateralization activation was only found in the left superior frontal gyrus, suggesting that the laterality was also modulated by the task state.In short, the brain laterality of cognitive control processing was modulated by the task in real-time and delay ways and also modulated by its state. In the task state fMRI, the cognitive control lateralization was presented in the left hemispheric cognitive control-related brain regions, and this is also reflected by the time course analysis; comparing to the task state, task-modulation brain spontaneous activity in resting state did not exist the hemispheric lateralization.