Trial-by-trial fMRI-neurofeedback dissociates fusiform and occipital contributions to face detection and recognition.

Self-regulation of specific brain regions can be achieved using neurofeedback with real-time functional magnetic resonance imaging (rt-fMRI). We leveraged this technique to dissect the role of two tightly interconnected areas implicated in face perception, by interleaving a visual task with upregulation of either the occipital (OFA) or fusiform face-responsive areas (FFA) in a trial-wise manner. Experimental participants (N = 22) successfully enhanced their target region when compared to yoked controls (N = 20). Regulation was face-selective, as evidenced by concomitant increases in other nodes of the face processing network. Critically, face detection was faster with enhanced FFA activity but hindered by enhanced OFA, whereas face identity recognition was optimal with concomitant increases in both FFA and OFA. These results argue against traditional face processing models assuming an information flow from posterior occipital to anterior fusiform cortex and instead support non-hierarchical models where FFA mediates initial face detection and OFA contributes to subsequent identity recognition.