Hemispheric lateralization of the face perception network

Introduction Face perception plays an important role in the human visual system as it serves as the basis for communication and social interaction for the majority of people. At the neuroanatomical level, the processing of faces is mediated by a distributed hierarchical neural network, which is often divided into a core system and an extended system (e.g. Haxby, 2000). The core system consists of several brain regions in the occipito-temporal cortex: the fusiform face area (FFA), the occipital face area (OFA) and an area in the posterior superior temporal sulcus (pSTS). Each region plays a different role in face processing. Recently, other regions such as the anterior STS or the ventral anterior temporal cortex have also been described as face-specific.

Methods In the present project we evaluated the lateralization of face perception regions in a large sample of subjects (n ~ 500). Brain activity was assessed with functional magnetic resonance imaging (fMRI) during a face perception task. For each region, hemispheric lateralization was described by a lateralization index (LI) using a toolbox which provides multiple options to compute LIs. We also assessed the influence of ultra-high-risk (UHR) for schizophrenia on lateralization.

Results As expected, our results showed, that face perception is lateralized to the right hemisphere at the population level. The data also underlined the large variability of the lateralization patterns both between subjects and between face-sensitive regions, depending on age, sex and handedness.

Conclusion The variability of the lateralization of the face processing network both between subjects and different brain regions plays an important role in psychiatric research since atypical lateralization patterns have been reported in the context of schizophrenia.