Functional connectivity of brain network during character imagery

Background Previous results indicate cognitive processes of brain areas usually activate during visual mental imagery [1], however, few studies address the functional connectivity between these active regions. In the present study, a lowfrequency (0–0.15 Hz) coherence method was used to analyze the event-related fMRI data from a task in which participants visualized digits and letters (termed as character imagery). The coherence method was discussed in detail in Sun et al [2]. A band-averaged coherence of 1 would indicate strong functional interaction between areas, and a coherence of 0 would indicate the total absence of such a relationship [2]. The brain networks include left IFG (inferior frontal gyrus), left FUS (fusiform gyrus), left CUN (cuneus) and left SPL (superior parietal lobule). All of the four ROIs (Regions of Interest) were selected based on previous studies [1,3]. Nine righthanded subjects participated in this study. The materials of the character imagery task were based on a subset of those used by Kosslyn et al [4]. Statistical parametric mapping analysis was performed using SPM2 running under Matlab 6.5. from Seventeenth Annual Computational Neuroscience Meeting: CNS*2008 Portland, OR, USA. 19–24 July 2008