Noninvasive studies of human brain function hold great potential to unlock mysteries of the human mind. The complexity of data generated by such studies, however, has prompted various simplifying assumptions during analysis. Although this has enabled considerable progress, our current understanding is partly contingent upon these assumptions. An emerging approach embraces the complexity, accounting for the fact that neural representations are widely distributed, neural processes involve interactions between regions, interactions vary by cognitive state, and the space of interactions is massive. Because what you see depends on how you look, such unbiased approaches provide the greatest flexibility for discovery.
Fig. 2 Attentional modulation of functional connectivity. (A) The guided activation theory of cognitive control posits that prefrontal cortex (PFC) sends feedback to posterior cortex to switch connectivity between cortex and establish task-relevant pathways. (B) Such pathways exist in the visual cortex of nonhuman primates: V4 shows enhanced coherence with the area of V1 containing receptive fields for the attended target. (C) This mechanism also supports category-based selection in human visual cortex: V4 shows stronger background connectivity with the fusiform face area (FFA) when faces are attended and with the parahippocampal place area (PPA) when scenes are attended.