Using functional magnetic resonance imaging (fMRI) and cortical unfold
ing techniques, we analyzed the retinotopy, motion sensitivity, and fu
nctional organization of human area V3A. These data were compared with
data from additional human cortical visual areas, including V1, V2, V
3/VP, V4v, and MT (V5). Human V3A has a retinotopy that is similar to
that reported previously in macaque: (1) it has a distinctive, continu
ous map of the contralateral hemifield immediately anterior to area V3
, including a unique retinotopic representation of the upper visual fi
eld in superior occipital cortex; (2) in some cases the V3A foveal rep
resentation is displaced from and superior to the confluent foveal rep
resentations of V1, V2, V3, and VP; and (3) inferred receptive fields
are significantly larger in human V3A, compared with those in more pos
terior areas such as V1. However, in other aspects human V3A appears q
uite different from its macaque counterpart: human V3A is relatively m
otion-selective, whereas human V3 is less so. In macaque, the situatio
n is qualitatively reversed: V3 is reported to be prominently motion-s
elective, whereas V3A is less so. As in human and macaque MT, the cont
rast sensitivity appears quite high in human areas V3 and V3A.