THREE PARIETAL CIRCUITS FOR NUMBER PROCESSING Dehaene Piazza Pinel Cohen 2003

Dec 13, 2010 12:30 PM

entire pdf is available online  (see Stan Dehaene's pubs).

Three Parietal Circuits for Number processing

work done at  Inserm-CEA  in Orsay (suburb of Paris to the SW at 20 km)

The triple-code model of number processing

predicts that, depending on the task, three distinct

systems of representation may be recruited: a quan-

tity system (a nonverbal semantic representation of

the size and distance relations between numbers,

which may be category specific), a verbal system

(where numerals are represented lexically, phono-

logically, and syntactically,much like any other type

ofword), and a visual system(inwhich numbers can

be encoded as strings of Arabic numerals)

(Dehaene, 1992; Dehaene & Cohen, 1995). We

initially proposed that the parietal activations dur-

ing number processing reflected solely the contri-

bution of the quantity system. However, it is now

First, the left perisylvian language network

clearly extends into the inferior parietal lobe.

Second, the posterior superior parietal lobs are strongly engaged

in visual attention processes that may contribute to visula processing of numbers.

So, it's crucial to distinguish which parietal sites are assoc with semantic repres of numerical quantity

and which merely correspond to nonspecific verbal or visual attention.

We propose  that  three circuits coexist in the parietal lobe anc caputre of of the

observed differences btwn arithmetic tasks

1)  a bilateral intrapareital system assoc with a cor quantity system,

2)  a region of the L angular gyrus assoc with verbal proc of numbers and

3) a posterior superior pareital system of spatial and nonspatial attention.

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