Deactivation In The Functional Brain Imaging Researches

Deactivation has been found frequently in previous functional brain imaging researches, which refers to the decrease in the regional brain activity during the cognitive task condition in comparison with the resting state. There is no universally accepted explanation of deactivation because its physiological mechanism is not well understood, and it is only recently that it has become a focus of systematic studies.Although the deactivation researches have already got many significant results, they mostly aim at confirming the brain regions that present the decrease of the brain blood flow. The response mode and space-time relation of these regions from overall and dynamic angle are left untouched. In this paper, one of the ROI-based functional connectivity analyses, within-condition interregional covariance analysis (WICA), is employed to analyze the interaction of the brain regions that show deactivation during different task states. The results open up a new perspective in the research of the deactivations in the future. A brief overview of the main work and discussion is introduced below:1. The study roundly introduces the foundation of neuroscience and primarily discussed the strongpoint of several function brain imaging methods, and the main calculation methods of the data from fMRI.2. The concept of the deactivation has been expatiated, and the processing resources reallocation theory has been accepted and primarily introduced after analyzing several explanations of the deactivation phenomenon. The function of regions which consistently show the task-independent deactivation has also been discussed and the concept of the default mode network in the brain has been advanced. Additionally, the deactivation during the Numerical Processing has been compared with the former studies.3. Three kinds of ROI-based functional connectivity analyses methods have been discussed in order to find the connectivity between regions. One of them, within-condition interregional covariance analysis, is employed to analyze and compare the interaction of the deactivation regions during the symbol orientation task and the number comparison task. Differences have been found between the two kinds of interaction, which indicate that the potential implication of special deactivation connectivity may be related to the different task or attention resource.