Digits, Dots, and the Numeric Brain

French scientists at INSERM studied 10 human volunteers to determine how the human brain encodes number. Using fMRI, the scientists scanned the volunteers' brains while showing them either images of certain numbers of dots, or a numeric symbol representing the same number.

This experiment reveals that the brain codes number symbols and fundamental numerical quantities slightly differently, he adds.

Coauthor Evelyn Eger of the French research institute INSERM and her colleagues scanned the brains of 10 volunteers using fMRI while showing them collections of dots. Computer analyses revealed that viewing different quantities of dots led to distinct brain activity patterns. Then the team showed the volunteers either collections of dots or digits of the same value. Analyses revealed slightly different brain activation patterns for digits and dots of the same numerical value, Eger says.

In both cases, activity was primarily in the parietal cortex. And the analyses used to evaluate the patterns revealed there was some overlap. A volunteer’s brain activation signature from viewing numbers could predict how many dots a subject had viewed, but not the other way around.

The researchers also found that the brain patterns shifted gradually with increasing numbers of dots, suggesting that numbers that are close in value activate patches of neurons that are close to each other in the brain. Digits, on the other hand, did not create this pattern of change in brain activity as numbers increased. _ScienceNews

It is interesting that early childhood math training at the Better Baby Institute in Philadelphia utilises large "flash cards" containing various numbers of dots.

Since the parietal lobe handles numbers of dots and equivalent numerical symbols differently, it is likely that other types of mental metaphor for number and quantity would likewise reveal distinctions in the neural correlates via scans. Very interesting research.