Structural and functional impairment of the face processing network in congenital prosopagnosia

There is growing consensus that accurate and efficient face recognition is mediated by a neural circuit comprised of a posterior "core" and an anterior "extended" set of regions. In a series of functional and structural imaging studies, we characterize the distributed face network in individuals with congenital prosopagnosia (CP) - a lifelong impairment in face processing - relative to that of matched controls. Interestingly, our results uncover largely normal activation patterns in the posterior core face patches in CP. More recently, we also documented normal activity of the amygdala (emotion processing) as well as normal, or even enhanced functional connectivity between the amygdala and the core regions. Critically, in the same individuals, activation of the anterior temporal cortex, which is thought to mediate identity processing, was reduced and connectivity between this region and the posterior core regions was disrupted. The dissociation between the neural profiles of the anterior temporal lobe and amygdala was evident both during a task-related face scan and during a resting state scan, in the absence of visual stimulation. Taken together, these findings elucidate selective disruptions in neural circuitry in CP, and are also consistent with impaired white matter connectivity to anterior temporal cortex and prefrontal cortex documented in these individuals. These results implicate CP as disconnection syndrome, rather than an alteration localized to a particular brain region. Furthermore, they offer an account for the known behavioral differential difficulty in identity versus emotional expression recognition in many individuals with CP. Meeting abstract presented at VSS 2014