Visual Areas in Macaque Cortex Measured Using Functional

ional homologies between the two species. Key words: visual cortex; visual areas; cortical magnification; fMRI; monkey; human; extrastriate cortex Functional magnetic resonance imaging (fMRI) provides new perspectives on the organization of visual cortex in both human and monkey brains (Logothetis et al., 1999; Wandell, 1999; Tolias et al., 2001; Vanduffel et al., 2001; Van Essen et al., 2001; Sereno et al., 2002). At present levels of sensitivity, human fMRI is useful for visualizing activity of the whole brain with millimeter resolution (Engel et al., 1997). In conventional monkey fMRI experiments, resolution can be at the submillimeter level (Logothetis et al., 2001), and for smaller volumes of interest, the use of implanted radio frequency coils permits voxel sizes as small as 0.012 #l (0.125 # 0.125 # 0.770 ; Logothetis et al., 2002). Using fMRI in a 4.7 T magnet and an anesthetized monkey, Logothetis et al. (1999) made preliminary measurements of the visual field organizati