CUE-INVARIANT ACTIVATION IN OBJECT-RELATED AREAS OF THE HUMAN OCCIPITAL LOBE

The extent to which primary visual cues such as motion or luminance ar e segregated in different cortical areas is a subject of controversy. To address this issue, we examined cortical activation in the human oc cipital lobe using functional magnetic resonance imaging (fMRI) while subjects performed a fixed visual task, object recognition, using thre e different primary visual cues: motion, texture, or luminance contras t. in the first experiment, a region located on the lateral aspect of the occipital lobe (LO complex) was preferentially activated in all 11 subjects both by luminance and motion-defined object silhouettes comp ared to full-field moving and stationary noise (ratios, 2.00 +/- 0.19 and 1.86 +/- 0.65, respectively). In the second experiment, all subjec ts showed enhanced activation in the LO complex to objects defined bot h by luminance and texture contrast compared to full-field texture pat terns (ratios, 1.43 +/- 0.08 and 1.32 +/- 0.08, respectively). An addi tional smaller dorsal focus that exhibited convergence of object-relat ed cues appeared to correspond to area V3a or a region slightly anteri or to it. These results show convergence of visual cues in LO and prov ide strong evidence for its role in object processing.