Long-range neural coupling through synchronization with attention.

In a crowded visual scene, we typically employ attention to select stimuli that are behaviorally relevant. Two likely cortical sources of top-down attentional feedback to cortical visual areas are the prefrontal (PFC) and posterior parietal (PPC) cortices. Recent neurophysiological studies show that areas in PFC and PPC process signals about the locus of attention earlier than in extrastriate visual areas and are therefore likely to mediate attentional selection. Moreover, attentional selection appears to be mediated in part by neural synchrony between neurons in PFC/PPC and early visual areas, with phase relationships that seem optimal for increasing the impact of the top-down inputs to the visual cortex.