Although faces are naturally seen in both left/right and up/down rotated views, virtually all fMRI work on the representation of face views has examined only left/right rotation around frontal views. Accordingly, we designed an fMRI adaptation study to test multiple cortical areas for up/down viewpoint selectivity. Face-selective regions of interest were determined in a block-designed scan comparing responses to faces versus houses. This identified five face-selective regions of interest: fusiform face area (FFA), occipital face area (OFA), lateral occipital complex (LOC), superior temporal sulcus (STS), and inferior frontal sulcus (IFS). Event-related scans with a cross-adaptation paradigm were used to examine BOLD signals in each face region. Subjects adapted to frontal, up 20?°, or down 20?° views followed by one of these as a test view, thus producing nine different adapt/test combinations. Twelve subjects with normal vision were scanned. An initial two way ANOVA examined effects of hemisphere and self-adaptation (i.e. identical test and adapt stimuli). This analysis showed an effect of hemisphere (right magnitudes larger) only in FFA, and significant adaptation effects in FFA (p 0.001), OFA (p 0.01), and IFS (p 0.028). A second ANOVA compared results for all adapt and test view combinations to their no adapt conditions in these three areas. FFA and IFS showed a significant cross-adaptation as well as self-adaptation. In general, upward faces produced greater adaptation than adaptation to frontal or downward faces in these areas, thus indicating view selective tuning in the up/down direction. Results in OFA, however, suggest an invariance to up/down head rotation. Thus, up/down head rotation is encoded in some but not all face selective cortical areas.
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