Behavioral/Systems/Cognitive Feature-Specific Attentional Priority Signals in Human Cortex

Human can flexibly attend to a variety of stimulus dimensions, including spatial location and various features such as color anddirection of motion. Although the locus of spatial attention has been hypothesized to be represented by priority maps encoded in several dorsal frontal andparietal areas, it is unknownhow the brain represents attended features. Herewe examined the distribution andorganization of neural signals related to deployment of feature-based attention. Subjects viewed a compound stimulus containing two superimposed motion directions (or colors) andwere instructed to perform an attention-demanding task on one of the directions (or colors).We found elevated and sustained functional magnetic resonance imaging response for the attention task compared with a neutral condition, without reliable differences in overall response amplitude between attending to different features. However, using multivoxel pattern analysis, wewere able to decode the attended feature in both early visual areas (primary visual cortex to humanmotion complex hMT) and frontal and parietal areas (e.g., intraparietal sulcus areas IPS1–IPS4 and frontal eye fields) that are commonly associatedwith spatial attention. Furthermore, analysis of the classifier weight maps showed that attending to motion and color evoked different patterns of activity, suggesting that different neuronal subpopulations in these regions are recruited for attending to different feature dimensions. Thus, our finding suggests that, rather than a purely spatial representation of priority, frontal and parietal cortical areas also contain multiplexed signals related to the priority of different nonspatial features