Are multiplication facts implemented by the left supramarginal and angular gyri?
A patient with presumed cerebral vasculitis showed preserved single digit multiplication facts and impaired single digit subtraction facts. Her ability to comprehend and manipulate numerical quantities was intact. Detailed analysis of her MRI-scan revealed a lesion involving the left parietal lobe including the supramarginal gyrus up to the intraparietal sulcus and extending posteriorly to involve part of the angular gyrus. This finding contradicts a previous report by Lee [Ann. Neurol. 48 (2000) 657] suggesting that these areas are critical for multiplication. In addition, this case contradicts the predicted association between subtraction and quantity manipulation, proposed by Dehaene's triple-code model [Cortex 33 (1997) 219].
van Harskamp
Natasja J
NJ
Department of Neuropsychology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK. n.harskamp@ion.ucl.ac.uk
Rudge
Peter
P
Cipolotti
Lisa
L
D000328:Adult; D003072:Cognition Disorders / Q000188:drug therapy*; D005260:Female; D005862:Gerstmann Syndrome; D006801:Humans; D008279:Magnetic Resonance Imaging; D008433:Mathematics; D010296:Parietal Lobe / Q000473:pathology*