The Deactivation And Default Mode Network Activity In Brain

As a non-invasive functional imaging technology, fMRI has been widely employed in cognitive researches. The focuses of previous studies are the task-related activation regions, and it is only recently that the deactivation regions it became the focus of systematic studies. The activation in fMRI reflects the activity increases of the nerve cell of the task-related regions, the regional blood flow increase and the changes of BOLD. However, the mechanics of the deactivation is not very clear now.The present study is designed to apply the theory of complex network in neuroscience and construct a functional brain network based on the data from fMRI. A brief overview of the main work and discussion is introduced below:1. The study roundly introduced the foundation of neuroscience and primarily discussed the function brain imaging and the main calculation methods of the data from fMRI.2. We mainly focused on the literature and theory investigations. The conception of deactivation, the probable physiological mechanism underling the deactivation and the relationship between deactivation and default mode brain networks had been reviewed. Further, the research background of default mode brain networks and its significance were emphasized. Additionally, we presented the complex network and applied it to the various fields.3. The study discusses the deactivation of the task of symbols' spatial orientation and we extracted the information from deactivation spots to establish the network. The network characters are analyzed to explain the reasons that the information of the brain transfer so fast and effective.4. The study not only expounds the relation between a node with the other nodes in local, but also analyzes the effect of the node in global by calculating degree and betweenness. We presume the key regions of deactivation in the symbols' spatial orientation task by locating the 10 nodes which have the largest degree and betweenness in the brain. Finally, the task independent characteristic is also found in two other experiments. Considering the relationship of deactivation and the resting brain network, the hit regions of the human brain default network were indicated.