Title: Organization of the normal and impaired face network in the human brain
Abstract: There is a growing realization that face perception is accomplished via the coordinated activity of a neuronal face processing network. However, many fMRI studies still utilize a localized approach mostly focusing on "core brain regions" (e.g., fusiform face area - FFA, occipital face area – OFA), often neglecting the extended face regions and importantly the interaction between these different regions at the network level. Our approach for decoding this network is to adapt tools coming from network science that allow us to characterize the topology and organization of the normal and impaired face network. In the first part of my talk, I will show results from a study in which we used the face inversion effect, which is a behavioral hallmark of face perception, to examine network mechanisms underlying face representation in the normal brain. In the second part of the talk, I will present an innovative approach we developed, which is geared towards tracking inter-regional stimulus-locked brain activation, to uncover marked topological differences in a brain network of higher-order visual regions in individuals with congenital prosopagnosia relative to controls. Finally, I will show some causal evidence for network based organization of the face system using data obtained from a simulated lesion model based on network embedding. Together, these studies offer a well-rounded characterization of the nature of face processing and its neuronal substrates. Our experimental and simulated results converge into a coherent picture of the topology of the face network and its dynamics. Finally, the network approach we have used enables to test neuronal and behavioral predictions as well as reveal new discoveries.