London, Nov 26 : Scientists, for the first time, have been able to offer a biological explanation for congenital prosopagnosia, sometimes known as face blindness, by mapping the disruption in neural circuitry of people suffering from this intriguing disorder.
People with congenital prosopagnosia are not able to recognize faces, while the ability to recognize other objects may be relatively intact.
For the study, a team of scientists from Carnegie Mellon University, Kings College in London and Ben-Gurion University in Israel, examined subjects aged 33 to 72 using diffusion tensor imaging and tractography.
By studying, the authors were able to show that, unlike that of normal brains, there was a reduction in the integrity of the white matter tracts in the brains of individuals with congenital prosopagnosic.
Moreover, the extent of the reduced white matter circuitry was related to the severity of the behavioral impairment.
White matter is one of the three main solid components of the central nervous system.
The white matter is the tissue through which messages pass between different areas of grey matter within the nervous system.
This discovery of reduced white matter circuitry could also lead to further understanding of other neurodevelopment disorders, such as developmental dyslexia, in which the same underlying neural alterations might be present.
The findings are also important as congenital prosopagnosia is, in many cases, inherited and so studies of this sort can help us understand the relationship between genetics and cortical development.
The study is published in the Nov. 23 online issue of Nature Neuroscience.