Fig. 3.
Time-dependent analysis of activity levels in right FFA. (A) BOLD signal time course averaged across subjects and percepts. The inserted plot shows average choice probabilities (expressed as AUC) for time points ta, tb, and tc. Asterisks mark choice probabilities significantly larger (P < 0.05, two-sided paired t test) than 0.5 in epochs tb (prestimulus baseline) and tc (peak response), indicating a relationship between higher activity levels and the perceptual decision for faces (individual data shown in Fig. S3). Note that there is no significant correlation between percept and signal at the earlier time point ta. (B) Stacked distributions of activity levels at time points ta, tb, and tc with the proportion of trials leading to faces and vase percepts indicated in red and blue, respectively. Distributions of FFA signal at ta and tb are very similar, but within this distribution face trials are reshuffled to higher signal intensities only at baseline time point tb as well as during the evoked response in tc. Fitted Gaussian distributions are indicated by dashed lines.