A sensory evoked response or precise anticipatory modulation? Mechanisms underlying the reported C1 modulation by...

Almost ten years ago, Kelly and collegues reported that the earliest component (i.e., the C1) of the visual evoked potential (VEP) could be modulated by spatial attention. Using a similar experimental design and data analysis methods, however, Baumgartner et al. (this issue) recently failed to provide confirmative evidence. In this commentary, I suggest that some minor differences in experimental design may account for the inconsistent results between the two studies. I also propose a hypothesis that the C1 effect reported in Kelly et al. may not necessarily reflect modulations of the initial visual evoked response in human V1.