Individuals with developmental prosopagnosia (DPs) have deficits with facial identity recognition in the absence of brain damage, low-level visual impairments, and intellectual difficulties. These deficits have a significant effect on the health and well-being of an estimated six million Americans, yet NIH currently funds only one project focused on developmental prosopagnosia (DP). The objective of the proposed project is to deepen our understanding of DP by identifying and investigating other deficits associated with it. The central hypotheses guiding this proposal are 1) developmental visual recognition deficits often co-occur, and 2) deficits with a particular category result from abnormalities in brain areas that respond preferentially to that category. The rationale for the project is that identifying deficits associated with DP will transform our understanding of the developmental and computational factors that cause DP and will provide a path to account for the different types of DP that exist. These hypotheses will be tested by pursuing the following specific aims.
For Aim 1 A, a large sample of DPs (n = 300) will be compared to controls with behavioral tests assessing the processing of faces, scenes, bodies, objects, words, biological motion, voices, color, and number. This approach will be complemented by Aim 1B, in which selectivity, population receptive fields, and effective connectivity of brain areas that respond preferentially to the categories assessed in Aim 1A will be compared in controls and a subset of the DPs (n = 60). It is predicted that both behavioral and neural measures will reveal broad deficits in the DPs and that the behavioral deficits will be linked with neural abnormalities. To address Aim 2A, performance on tasks measuring different aspects of scene processing will be contrasted in DPs with scene processing deficits (n = 30), DPs with normal scene processing (n = 30), and controls.
For Aim 2 B, selectivity, population receptive fields, and multivariate classification accuracy in scene areas and effective connectivity between scene areas will be used to identify neural differences between the three groups. The working hypothesis for Aim 2 is that DPs with scene deficits will exhibit reduced performance with many or all scene tasks, and their functional responses in and connectivity betweeen scene areas will be abnormal. Execution of this project will result in: 1) identification of behavioral deficits and neural abnormalities associated with DP, and 2) determination of the behavioral and neural characteristics of two types of DP distinguished by scene processing. This project is innovative, because it will be the first systematic investigation of non-face processing in DP and it will demonstrate how to account for DP heterogeneity. In addition, the work will utilize a novel two-step research process: online behavioral testing with the largest sample of DPs ever tested, followed by neuroimaging with DPs who have particular behavioral profiles. The proposed project is significant, because DP is a serious social handicap and this project will lead to a new conception of DP and other visual recognition deficits that emphasizes co-occurring conditions and factors with broad effects.
The proposed project is relevant to public health, because developmental prosopagnosia is estimated to impact six million American and 130 million people worldwide. This project will determine the extent of cognitive and neural abnormalities in developmental prosopagnosia, which we expect will lead to a new perspective on developmental visual recognition disorders which emphasizes that a variety of deficits exist, often co-occur, and are caused by factors that have effects across functional divisions in cortex. As a result, the proposed research is relevant to NIH?s mission to develop fundamental knowledge that enhances health and well-being and reduces the burdens of disability.
