A German team has found that congenital prosopagnosia (CP), a conditon where a person has a hard time recognizing faces, is genetically inherited. Thomas Grüter, himself a CP sufferer, and his team at the Institute for Human Genetics in Münster, Germany traced CP in 7 families and found evidence that CP is inherited through a single genetic defect.
The team recruited members of a prosopagnosia support group and their families into the study, plus Grüter's own relatives. Using a questionnaire to identify prosopagnosia symptoms, the team found 38 prosopagnosics in seven families. By plotting the condition on family trees, the team showed that the inheritance pattern is consistent with the trait being carried by a single gene: just one defective copy of the gene could make the carrier face-blind.
Other people suffer from prosopagnosia due to trauma to the brain that caused brain damage. But for those who have prosopagnosia from birth the open question has been whether the condition is the result of trauma or toxin exposure during early development or inheritance.
The fact that this disorder can be caused by genetic defect demonstrates that at least for one important cognitive ability the brain's structure that supports that ability is coded for genetically. This result then is another piece of evidence against a blank slate view of the brain.
PITTSBURGH--Recognizing faces is effortless for most people, and it's an ability that provides great evolutionary and social advantages. But this ability is impaired in people who have suffered brain damage or in those with a rare congenital condition, and research by Carnegie Mellon University psychologists reveals startling insights into how the brains of those individuals operate. Psychology Professor Marlene Behrmann and postdoctoral associate Galia Avidan have found that people with congenital prosopagnosia--in which their ability to recognize faces is impaired from birth--are not just deficient at recognizing individuals they know, but they are also poor at simply discriminating between two faces when presented side by side. The researchers also have discovered through functional Magnetic Resonance Imaging (fMRI) scans that, contrary to their expectations, the regions of the brain that are activated when normal individuals perceive and recognize faces also are activated in individuals with congenital prosopagnosia (CP). Behrmann and Avidan will summarize the results of their findings in the April issue of the journal Trends in Cognitive Sciences.
Behrmann and Galia said that much remains to be learned from the individuals in their research. They have begun to examine the anatomical details of the brains of their participants, and preliminary findings show that some brain structures are smaller in the region known to control face recognition.
Did Michelangelo or Leonardo Da Vinci have a larger region of their brains for facial recognition? Did they from birth have more neurons dedicated to understanding facial structures? Or were their mental gifts due to more general enhancements of cognitive abilities?
|Share |||Randall Parker, 2005 April 05 04:55 PM Brain Genetics|