Face perception elicits activation within a distributed cortical network in the human brain. The network includes visual (‘‘core’’) regions, as well as limbic and prefrontal (‘‘extended’’) regions, which process invariant facial features and changeable aspects of faces, respectively. We used functional Magnetic Resonance Imaging and Dynamic Causal Modeling to investigate effective connectivity and functional organization between and within the core and the extended systems. We predicted a ventral rather than dorsal connection between the core and the extended systems during face viewing and tested whether valence and fame would alter functional coupling within the network. We found that the core system is hierarchically organized in a predominantly feedforward fashion, and that the fusiform gyrus (FG) exerts the
dominant influence on the extended system. Moreover, emotional faces increased the coupling between the FG and the amygdala, whereas famous faces increased the coupling between the FG and the orbitofrontal cortex. Our results demonstrate content-specific dynamic alterations in the functional coupling between visuallimbic and visual-prefrontal face-responsive pathways.
Face perception elicits activation within a distributed cortical network. Axial sections, taken from a representative subject, illustrate activation within the core (IOG-inferior occipital gyrus, FG-fusiform gyrus, STS - superior temporal sulcus) and extended (AMG-amygdala, IFG-inferior frontal gyrus, OFC-orbitofrontal cortex) systems. Coordinates are in the Talaraich space. L 5 left, R 5 right.
(click to enlarge) Alterations in effective connectivity within the core and the extended systems induced by all faces, emotional faces, and famous faces. Black connections indicate significant regional effects, red connections indicate significant bilinear effects, and dotted lines indicate non-significant effects.
Monday, July 02, 2007
Face perception by distributed cortical networks.
Continuing to pass along material from talks given at the recent ASSC meeting, here is the abstract and some figures from an interesting bit of work on face perception (PDF here).