Orienting to the Environment: Separate Contributions of Dorsal and Ventral Frontoparietal Attention Networks

The most important contribution of brain imaging in the last twenty years has been to show directly a separation between source signals and modulations of sensory processing, and to identify a set of dorsal frontoparietal regions, or dorsal frontoparietal attention network (DAN), which are consistently involved in the selection of task-relevant stimuli and responses. A second general contribution of neuroimaging has been to show clearly that both goal-driven and stimulus-driven forms of attention are mediated by a single neural system, the dorsal frontoparietal network and associated subcortical regions (e.g., superior colliculus and perhaps pulvinar), and that a more fundamental distinction at the neural level is between orienting, implemented by the DAN, and reorienting, jointly implemented by the DAN and a separate ventral frontoparietal attention network (VAN). The VAN is tuned to all those circumstances in which endogenous expectations do not match sensory inputs, and as such is of fundamental importance for survival. One of the most interesting aspects of this network is its right hemisphere lateralization, which has allowed researchers to formulate questions about hemispheric asymmetries of attention in the healthy and damaged brain in terms of specific neural substrates.