Scientists at the Stanford University School of Medicine have shown for the first time how brain function differs in people who have math anxiety from those who don’t.
A series of scans conducted while second- and third-grade students did addition and subtraction revealed that those who feel panicky about doing math had increased activity in brain regions associated with fear, which caused decreased activity in parts of the brain involved in problem-solving.
The paper itself: Christina B. Young, Sarah S. Wu, and Vinod Menon. The Neurodevelopmental Basis of Math Anxiety. Psychological Science OnlineFirst, published on March 20, 2012 as doi:10.1177/0956797611429134. A pdf file is avalable here.