Brain network dynamics underlying visuospatial judgment: an FMRI connectivity study

■ Previous functional imaging research has consistently indi-cated involvement of bilateral fronto-parietal networks during the execution of visuospatial tasks. Studies with TMS have sug-gested that the right hemispheric network, but not the left, is func-tionally relevant for visuospatial judgments. However, very little is still known about the interactions within these fronto-parietal networks underlying visuospatial processing. In the current study, we investigated taskmodulation of functional connectivity (instan-taneous correlations of regional time courses), and task-specific effective connectivity (direction of influences), within the right fronto-parietal network activated during visuospatial judgments. Ten healthy volunteers performed a behaviorally controlled visuo-spatial judgment task (ANGLE) or a control task (COLOR) in an fMRI experiment. Visuospatial task-specific activations were foun