To attend class, backpack-carrying pupils from Atuler village in Sichuan province must take on an 800m rock face, scrambling down rickety ladders and clawing their way over bare rocks as they go.
The ten scrambled images were modified from the selected faces, scrambled with Adobe Photoshop software using a ripple distortion filter.
In each functional run, the sequence of 'scrambled faces, faces, scrambled non-faces, non-faces' was repeated four times (in total 16 blocks and 256 images).
The localizer scan was acquired first and comprised 1 fMRI run lasting approximately 8 min. Within the run, there were 6 repetitions of the 4 experimental conditions: words, faces, scrambled words, and scrambled faces.
The distracters were presented during the delay interval between the memoranda and probes, and consisted of morphed anxiety-inducing angry faces, neutral faces, and scrambled faces (50% of the distracters were females and 50% were males).
Here, we consider only the parameter estimate for the canonical HRF [cf. Henson et al., 2003], images of which were entered into a repeated-measures ANOVA with three conditions corresponding to familiar faces, unfamiliar faces, and scrambled faces (correcting for nonsphericity).
For the functional localizer scan, the general linear model (GLM) modeled the face, word, scrambled face or scrambled word stimuli as explanatory variables (EVs), convolved with a hemodynamic response function (HRF).
We therefore examined a subset of brain regions, FFA and OFA, respectively, that were defined in individual participants by the face versus scrambled face contrast in our 2nd, "functional localizer" phase (Eger et al. 2005).
The resulting contrasts for each subject were transformed onto surface space, then smoothed on the surface to 5-mm FWHM, and averaged across the group to create a surface-based group map of the face versus scrambled face and word versus scrambled word contrasts.
