Enhanced amygdala responses to emotional versus neutral schematic facial expressions.

Human facial emotional expressions are complex. This may confound studies examining brain responses to these stimuli in control and clinical populations. However, several lines of evidence suggest that a few elementary facial features convey the gist of emotional expressions. Using fMRI, we assessed brain responses to line drawings of emotionally valenced (i.e. angry and happy) and neutral faces in healthy human subjects. Significantly increased fMRI signal was found in the amygdala, hippocampus and prefrontal cortex in response to emotional vs neutral schematic faces. Although direct comparisons of schematic and human faces will be needed, these initial results suggest that schematic faces may be useful for studying brain responses to emotional stimuli because of their simplicity relative to human faces.