A brain for numbers
Marco Sandrini2009, Cortex
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Abstract
Healthy human brains come equipped with several circuits that contribute to number processing. Nature and nurture interact to produce a unique combination of core skills and more sophisticated abilities, by building on a handful of auxiliary routes (e.g., verbal language, body knowledge and visuospatial attention). Transcranial magnetic stimulation (TMS) studies on number processing will be here succinctly reviewed, in light of their most stimulating and challenging contributions. New research directions will be pointed out, that might enhance their theoretical impact. (M. Sandrini). a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c o r t e x ARTICLE IN PRESS 0010-9452/$ -see front matter ª
Key takeaways
- Such alternative accounts do not hold for Andres et al.'s study (2005), in which TMS did interact with both hemisphere and numerical distance.
- In contrast, TMS data show that the left IPS is critical for processing of symbolic and non-symbolic numerosity, whereas the right IPS seems involved in the processing of continuous quantities.
- Future TMS studies should address timing issues, with an eye to the interplay between numbers and other cues, in getting access to the spatial attention system.
- Kansaku et al. (2007) found that left ventral premotor cortex (vPM) rTMS (but not supplementary motor area, SMA) interferes with serial cumulative counting of large numbers and not with recursive counting of small numbers, or letter reciting.
- If the numerical representation in the IPS is abstract, application of TMS after adaptation to the Arabic numerals (e.g.
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