Lateralised contributions of the fusiform cortex to face detection

Neuronal populations in ventral visual cortex are often classified according to the stimuli that elicit their strongest excitatory response. Using such preferred or effective stimuli, receptive fields have been mapped to better understand links between visual responses and behaviour. For example, face-selective regions in human ventral cortex, which prefer faces over objects, are thought to have small, foveally-biased receptive fields, supporting the recognition of subtle facial cues. However, little is known about how face selectivity interacts with stimulus location, or whether selective responses to peripheral faces are altered when competing visual inputs are present. Here, we used ultra-fast 7T fMRI to test whether the Fusiform Face Area (FFA) continues to prefer faces when they occur in the periphery or with competing inputs. We found that face-selective responses in the FFA were robust to competition, whereas object-selective responses in the neighbouring area of the Medial Temporal Lobe (MTL) were reduced. The left FFA showed a contralateral bias that encoded the spatial location of peripheral faces, consistent with a role in orienting toward socially relevant stimuli. In contrast, the right FFA exhibited a stronger category bias that was largely invariant to stimulus position and persisted under competition, suggesting a potential role in evaluating faces prior to fixation. Taken together, these findings reveal lateralised contributions of fusiform cortex to face detection: the left FFA supports the localisation of faces, while the right FFA provides robust categorical information. Together, the findings highlight how the human face-selective network is adapted to detect and prioritise faces under naturalistic viewing conditions.