Effects of Low-Spatial Frequency Components of Fearful Faces on Fusiform Cortex Activity  Joel S. Winston, Patrik Vuilleumier, Raymond J. Dolan  Current Biology  Volume 13, Issue 20, Pages 1824-1829 (October 2003) DOI: 10.1016/j.cub.2003.09.038

Figure 1 Example Stimuli and Experimental Design (A) Six males and six females were selected from the KDEF database of faces (D. Lundqvist and J.-E. Litton, personal communication; photographic face set available from the Department of Neurosciences, Karolinska Hospital, Stockholm, Sweden). The example stimulus shows a neutral female at low spatial frequencies and a fearful male at high spatial frequencies. Perception is typically dominated by HSF cues when looking at such stimuli nontachistoscopically. To see the LSF, squint or increase the viewing distance. (B) Experimental design: all hybrids contained a male and a female face; subjects could report either the low or high SF by judging the gender of the face perceived during rapid presentations. At each SF, the face could be either fearful or neutral, resulting in a 2 × 2 × 2 factorial design. A total of 288 stimuli were used (each of 12 stimuli crossed with 6 of the opposite gender, with 4 possible pairings of expressions: neutral/neutral, fearful/neutral, neutral/fearful, fearful/fearful). Current Biology 2003 13, 1824-1829DOI: (10.1016/j.cub.2003.09.038)

Figure 2 Fusiform Response to Fear in Low Spatial Frequencies (A–C) Sagittal, coronal, and horizontal sections of SPMs showing response in right fusiform cortex in the contrast of main effect of LSF fear (LSF fear–LSF neutral). Peak at x, y, z = 39, −48, −27; Z = 4.33; p < 0.05 SVC. Activation displayed at p < 0.001 uncorrected on the mean structural image from the group of subjects. (D) Parameter estimates from peak fusiform voxel showing response to LSF fear is greater than to LSF neutral independent of subjects' report (i.e., whether they report perceiving LSF or HSF stimulus). Current Biology 2003 13, 1824-1829DOI: (10.1016/j.cub.2003.09.038)

Figure 3 Behavioral Effect of Fear in LSF (A) Relation between fear in LSF and subjects' report suggesting a trend to slower RTs when fear is present in LSF and the subject reports an HSF stimulus. (B) Significant correlation between fusiform activity to main effect of LSF fear and behavioral interaction between report and LSF fear in reaction times (p < 0.05). This indicates that greater fusiform activity to LSF fear stimuli relates to a behavioral slowing when responding to the HSF components of the stimulus. Current Biology 2003 13, 1824-1829DOI: (10.1016/j.cub.2003.09.038)

Figure 4 Orbitofrontal Cortex Shows an Interaction between Report and LSF Fear (A) SPM showing response in right orbitofrontal cortex in the interaction between LSF fear and behavioral report. Peak at x, y, z = 24, 42, −15; Z = 3.41; p < 0.001 uncorrected. The display is shown as in Figure 2A. (B) Parameter estimates from peak voxel in orbitofrontal cortex showing response to LSF fear is greater than to LSF neutral only when subjects report LSF components of the stimulus. (Simple effect of LSF fear when LSF reported, Z = 3.43; simple effect of LSF fear when HSF fear reported, Z = −0.82). Current Biology 2003 13, 1824-1829DOI: (10.1016/j.cub.2003.09.038)