Processing of performance-matched visual object categories: faces and places are related to lower processing load in the frontoparietal executive network than other objects.

This study aimed to explore the differential role of the frontoparietal network in processing different visual object categories, matched for difficulty level, during a 1-back paradigm. To achieve this goal, we first mapped the effort-related frontoparietal saliency network, by contrasting activation elicited by face, object, place, body and verbal stimulus categories, which were matched for performance level, and speed of processing, with difficult scrambled stimuli. We then computed the weight of object predictors on that specific network, using an independent orthogonal analysis. Overall, our results demonstrated that face (and to some extent also places) stimuli were associated with lower processing load in regions of the frontoparietal network comparing to other visual categories, suggesting that face/place processing does require to a much smaller extent the recruitment of the frontoparietal control network than any other object categories. Thus, face detection and place detection seem to be routed in specific neuronal systems that readily encode the holistic nature of this type of objects. We conclude that the more limited recruitment of frontoparietal networks reflects the automaticity of face and place processing and their smaller dependence on general capacity limits.