Abstract
Attention has an important role in our ability to individuate objects across variations in both space and time. Many studies have investigated how attention can dynamically alter the spatial tuning properties of visual neurons, but much less is known about whether attention can alter the temporal properties of the visual system. Previously, we have shown that temporal tuning functions of individual human visual areas can be reliably measured with fMRI. Here, we investigated whether spatial attention can enhance the temporal processing capacity of cortical visual areas during object processing. Subjects were instructed to attend to one of two simultaneously presented RSVP sequences of face and houses, which were presented to the left and right of central fixation. Presentation rate varied from 2–30 items/second. Spatial attention led to an overall increase in response amplitudes in early areas V1–V3, but did not alter the temporal frequency response profile of these areas. In V4v and the fusiform face area, attention not only led to enhanced response amplitudes but also led to a rightward shift in the temporal frequency response profile, indicating a shift in peak sensitivity toward higher temporal rates. In comparison, the parahippocampal place area showed weak evidence of attentional modulation. Our results suggest that spatial attention is capable of altering the temporal processing capacity of some high-level visual areas. These results may be of functional significance when an observer must identify an object under temporally demanding conditions.