Differential selectivity for dynamic versus static information in face selective regions

摘要

Neuroimaging studies have identified multiple face-selective regions in human cortex but the functional division of labor between these regions is not yet clear. A central hypothesis, with some empirical support, is that face-selective regions in the superior temporal sulcus (STS) are particularly responsive to dynamic information in faces, whereas the fusiform face area (FFA) is more sensitive to the static or invariant properties of faces. Here we quantitatively tested this hypothesis by measuring the magnitude of response in each region to both dynamic and static stimuli. Consistent with the hypothesis, we found that the right FFA and right occipital face area (OFA) responded similarly to movies of faces and to static images of faces from these same movies. By contrast the face-selective region in the right posterior STS (pSTS) responded nearly three times as strongly to dynamic faces as to static faces, and a face-selective region in the right anterior STS (aSTS) responded to dynamic faces only. Both of these regions also responded much more strongly to moving faces than moving bodies, indicating that they are engaged specifically in processing dynamic information from faces, not more generally in processing any dynamic social stimuli. A third face-selective region in the posterior-continuation of the STS (pcSTS) responded similarly to dynamic and static faces. The strong selectivity of face-selective regions in the pSTS and aSTS, but not the FFA, OFA or pcSTS, for dynamic information from faces demonstrates a clear functional dissociation between different face-selective regions, and provides further clues into their function.