Trade-off in sensitivity between object identity and viewpoint in both the dorsal and ventral visual streams

The ventral visual stream exhibits a trade-off between sensitivity to an object’s identity and identity-preserving transformations across cortical regions: as sensitivity to identity increases, sensitivity to changes in such things as viewpoint decreases and vice versa. Recent findings suggest that the dorsal visual stream is more involved in perceptual object processing than originally hypothesized. However, it remains unclear whether this trade-off also exists within the dorsal stream, and, if so, how it relates to the ventral stream’s trade-off. Participants viewed rotating tools in an MRI scanner, and multivariate analyses were conducted to quantify voxels’ ability to discriminate between objects and track their viewpoints. Voxels’ classification and viewpoint tracking performance were negatively correlated within both streams, suggesting trade-offs in sensitivity. The degree of trade-off was also highly correlated between the streams across individuals. Examining the relationship between sensitivity levels and voxels’ spatial position revealed that object identity sensitivity increased moving anteriorly along the ventral stream, but no other significant spatial gradients were found. The presence of a sensitivity trade-off in the dorsal stream and of a functional relationship between the streams’ trade-offs extend current knowledge of the dorsal stream, in particular its commonalities with the ventral stream and its potential greater involvement in perceptual processing.