Separate Face and Body Selectivity on the Fusiform Gyrus

Abstract

Recent reports of a high response to bodies in the fusiform face area (FFA) challenge the idea that the FFA is exclusively selective for face stimuli. We examined this claim by conducting a functional magnetic resonance imaging experiment at both standard (3.125 ϫ 3.125 ϫ 4.0 mm) and high resolution (1.4 ϫ 1.4 ϫ 2.0 mm). In both experiments, regions of interest (ROIs) were defined using data from blocked localizer runs. Within each ROI, we measured the mean peak response to a variety of stimulus types in independent data from a subsequent event-related experiment. Our localizer scans identified a fusiform body area (FBA), a body-selective region reported recently by Peelen and Downing (2005) that is anatomically distinct from the extrastriate body area. The FBA overlapped with and was adjacent to the FFA in all but two participants. Selectivity of the FFA to faces and FBA to bodies was stronger for the high-resolution scans, as expected from the reduction in partial volume effects. When new ROIs were constructed for the high-resolution experiment by omitting the voxels showing overlapping selectivity for both bodies and faces in the localizer scans, the resulting FFA* ROI showed no response above control objects for body stimuli, and the FBA* ROI showed no response above control objects for face stimuli. These results demonstrate strong selectivities in distinct but adjacent regions in the fusiform gyrus for only faces in one region (the FFA*) and only bodies in the other (the FBA*).

Visual word processing and experiential origins of functional selectivity in human extrastriate cortex

“…We speculate that many of the inconsistencies in the prior literature result from the fact that the cLSSR is very small compared with the size of typical imaging voxels, so when imaging at standard resolutions the response profile of this region will inevitably be averaged with neighboring cortex, and in some cases the region may be missed altogether (see also ref. 7). The present data resolve these ambiguities by showing that when scanning is conducted at relatively high resolution, a region that is strongly selective for letter strings (but not for words vs. consonant strings) can be found in most subjects tested.…”

“…H uman extrastriate cortex contains a number of regions that respond selectively to specific categories of visual stimuli (1): the fusiform face area (FFA), which responds selectively to faces (2,3); the parahippocampal place area, which responds selectively to scenes (4,5); and the extrastriate body area and fusiform body area, which respond selectively to human bodies and body parts (6)(7)(8). Each of these regions can be found in roughly the same anatomical location in most subjects.…”

The fusiform face area: a cortical region specialized for the perception of faces

“…Third, the 'FFA' was defined as a large square ROI, over a centimetre on a side, a method that guarantees the inclusion of voxels neighbouring but not in the FFA. Thus, it is possible, for example, that any training effects on Greebles may arise from the body-selective 'fusiform body area' (FBA; Peelen & Downing 2005;Schwarzlose et al 2005) which is adjacent to the FFA (see §3e) rather than from the FFA itself. Finally, 'activation' was defined as the sum across the 64 voxels in the ROI of t-values resulting from a comparison of upright to inverted responses within each voxel (after excluding all t-values less than 0.1).…”

“…Indeed, the fact that some people with acquired prosopagnosia have apparently normal object recognition (Wada & Yamamoto 2001;Humphreys 2005) suggests that cortical regions that are necessary for face recognition are not necessary for object recognition. Finally, Tsao's single-unit recordings from face-selective patches in monkeys (see §2d ) indicate that non-preferred responses in face-selective regions are virtually non-existent (Tsao et al 2006), suggesting that the non-preferred responses observed in the FFA with fMRI may result from blurring of responses from an extremely faceselective FFA with neighbouring non-face-selective cortex (Schwarzlose et al 2005). For all these reasons, we doubt that non-preferred responses in the FFA play an important role in coding for nonface objects.…”

Faces, Bodies, Social Vision as Agent Vision, and Social Consciousness

“…Another cortical area, near the middle occipital gyrus has come to the foreground because it appeared selectively activated during presentation of body stimuli and was named the extrastriate body area(EBA) (Downing, Jiang, Shuman, & Kanwisher, 2001;Grossman & Blake, 2002;Peelen & Downing, 2005;Sakreida, Schubotz, Wolfensteller, & von Cramon, 2005;Spiridon, Fischl, & Kanwisher, 2006). More recently, however, it has been shown that an area in the midfusiform cortex is also selectively activated in response to whole bodies, and this led the authors to propose a division of the midfusiform cortex in a face vs. body sensitive set of voxels(fusiform body area, FBA) (Peelen & Downing, 2005;Schwarzlose, Baker, & Kanwisher, 2005;Spiridon et al, 2006). The latter result is consistent with our previous findings on the role of the fusiform cortex in body processing (Figure 3.1) (Hadjikhani & de Gelder, 2003).…”