The task dependent interaction of the deactivation regions

Although deactivation has been found frequently in former functional brain imaging researches, only recently has it become a focus of systematic study because of its not well understood physiological mechanism. However, most of the researches concentrated on the brain areas that would present deactivation, and, to our knowledge, the deactivation connectivity between these brain areas during the cognitive tasks has rarely been reported in literature. In this work, using the functional connectivity method WICA (within-condition interregional covariance analysis), we analyzed the deactivations in two different cognitive tasks—symbol orientation and number comparison. The results revealed deactivations in the posterior cingulate, precuneus, anterior cingulate and prefrontal cortex in both tasks. However, the interaction between the deactivated regions shows many differences. Our result further indicates that the potential implication of special deactivation connectivity may be related to the different task or attention resource. Further research is needed to clarify the exact reason. Contributed equally to this work Supported by the National Natural Science Foundation of China (Grant Nos. 60472017 and 30670699), Ministry of Education of China (Grant No. NCET-06-0277) and the Research Fund for the Doctoral Program of Higher Education (RFDP) (Grant No. 021010)