Attentional modulation of early visual areas.

This special issue of Cognitive Neuroscience focuses on the debate regarding whether spatial attention can rapidly modulate the event-related potential (ERP) C1 component, which reflects the initial feedforward signal in V1. A discussion paper by Baumgartner, Graulty, Hillyard, and Pitts (this issue) included an empirical experiment that failed to replicate the significant C1 attention effects of Kelly, Gomez-Ramirez, and Foxe. Commentaries were received by Ding (this issue), Klein (this issue), Pourtois, Rossi, Vuilleumier, and Rauss (this issue), Kelly and Mohr (this issue), Slagter, Alilovic, and Van Gaal (this issue), and Fu (this issue). The author response highlighted that C1 attention effects may be obtained in only limited conditions, considered problems of investigating C1 attention effects, and proposed future strategies. An empirical paper by Herde, Rossi, Pourtois, and Rauss (this issue) found that C1 was modulated by stimulus predictability, which indicates higher-level cognitive processes can modulate V1. A second discussion paper (Slotnick, this issue) compared experimental parameters across spatial attention studies and concluded certain stimulus, task, and analysis conditions were more likely to produce significant C1 attention effects. Commentaries were received by Fu (this issue), Qu and Ding (this issue), Zani and Proverbio (this issue), Pitts and Hillyard (this issue), Di Russo (this issue), and Mohr and Kelly (this issue). The author response included a more in depth analysis, and several studies that observed significant C1 attention effects survived critical analysis. The topics considered in this issue have clarified the current state of this debate and provided directions for future research.