A new article in PNAS identified two distinct task-control networks by "applying graph theory to resting state functional connectivity MRI data" (Dosenbach et al., 2007). A press release from Washington University in St. Louis includes this quote from one of the authors (Steven Petersen, Ph.D.):
To enhance their analysis [resting state functional connectivity MRI], Dosenbach and Petersen turned to graph theory, a branch of mathematics that visually graphs relationships between pairs of objects.How many degrees away are you?
"A similar approach is used in the party game Six Degrees of Kevin Bacon," Petersen notes. "You use paired connections — appearances in the same movie, marital relationships — to go from one actor or actress to another until you've identified a chain of connections linking Kevin Bacon and another performer that wasn't immediately obvious."
Steven E. Petersen, Ph.D., the James S. McDonnell Professor of Cognitive Neuroscience and director of the Division of Neuropsychology in Neurology in the School of Medicine, was elected as a fellow of the American Association for the Advancement of Science (AAAS).
Individuals are elected as AAAS fellows in recognition of their efforts toward advancing science or fostering applications that are deemed scientifically or socially distinguished.
Dosenbach NU, Fair DA, Miezin FM, Cohen AL, Wenger KK, Dosenbach RA, Fox MD, Snyder AZ, Vincent JL, Raichle ME, Schlaggar BL, Petersen SE. (2007). Distinct brain networks for adaptive and stable task control in humans. PNAS 2007 Jun 18; [Epub ahead of print].
Control regions in the brain are thought to provide signals that configure the brain's moment-to-moment information processing. Previously, we identified regions that carried signals related to task-control initiation, maintenance, and adjustment. Here we characterize the interactions of these regions by applying graph theory to resting state functional connectivity MRI data. In contrast to previous, more unitary models of control, this approach suggests the presence of two distinct task-control networks. A frontoparietal network included the dorsolateral prefrontal cortex and intraparietal sulcus. This network emphasized start-cue and error-related activity and may initiate and adapt control on a trial-by-trial basis. The second network included dorsal anterior cingulate/medial superior frontal cortex, anterior insula/frontal operculum, and anterior prefrontal cortex. Among other signals, these regions showed activity sustained across the entire task epoch, suggesting that this network may control goal-directed behavior through the stable maintenance of task sets. These two independent networks appear to operate on different time scales and affect downstream processing via dissociable mechanisms.
Subscribe to Post Comments [Atom]