Contextual modulation in V1: the Rossi-Zipser controversy.

A recent study (Rossi et al. 2001) implied the absence of figure-ground based contextual modulation in macaque V1, in contrast to the study on which it was modelled (Zipser et al. 1996). We suggest that Rossi et al. may have underestimated the extent of modulation by considering only positive and not also negative modulation and that their data may have shown figure-ground based contextual modulation. We then suggest a paradigm to assess whether it reflects figure-ground segregation, boundaries, or both.