Attention Improves Classification Performance of Locations in Ventral and Dorsal Visual Pathways

Visual processing is divided into a ventral and dorsal pathway, thought to be important for object recognition and spatial cognition, respectively. Yet both streams encode shape and spatial information, and both are modulated by attention and task demands. This study compared how attention influences fMRI bold responses in a ventral region (fusiform gyrus, FG) and dorsal region (superior parietal gyrus, SPG). Specifically, using multivariate pattern analysis within each region, we examined whether attention modulated spatial location classification performance. During fMRI scans, participants performed one of 3 possible tasks: a 1-back task under attend-to-shape (detect a shape repetition); a 1-back task under attend-to-location (detect a location repetition); and a passive task (detect a color change of the fixation point). Each task had identical stimulus presentations, in order to isolate attentional effects. Spatial location classification was performed using support vector machine (SVM) across the regions of interest, including FG in the ventral pathway and SPG in the dorsal pathway. FG and SPG each showed higher spatial classification accuracies in both the attend-to-shape and attend-to-location conditions compared to chance levels for SVM classification approach. In addition, FG and SPG each showed higher spatial classification accuracies in both attention conditions compared to the passive condition for SVM classification algorithm. These results suggest that attention, either to the shape or location of a stimulus, enhances spatial representations not only in the dorsal pathway but also in the ventral pathway, supporting the view that spatial representations are modulated by attention along both streams. The findings, including why attention to shape improves spatial classification, will be discussed.