Friday, May 25, 2007

A neural link between hand muscle excitability and numerical counting

Sato et al. do an interesting experiment showing that excitability of our hand muscles changes when we perform a visual (non-numerical) counting task, reinforcing the idea that finger counting represents an basic embodied strategy for number learning. (PDF here.) Their abstract:

Developmental and cross-cultural studies show that finger counting represents one of the basic number learning strategies. However, despite the ubiquity of such an embodied strategy, the issue of whether there is a neural link between numbers and fingers in adult, literate individuals remains debated. Here, we used transcranial magnetic stimulation to study changes of excitability of hand muscles of individuals performing a visual parity judgment task, a task not requiring counting, on Arabic numerals from 1 to 9. Although no modulation was observed for the left hand muscles, an increase in amplitude of motor-evoked potentials was found for the right hand muscles. This increase was specific for smaller numbers (1 to 4) as compared to larger numbers (6 to 9). These findings indicate a close relationship between hand/finger and numerical representations.

1 comment:

Murky Thoughts said...

They seem to have neglected to mention their postulate that neural links can not be established by learning. As I wouldn't dream of embracing a postulate so prima facie absurd myself, I feel obliged to judge these folks as failing utterly to settle the ambiguity they tell us they set out to resolve and that they claim to have resolved.

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