Numbers within Our Hands: Modulation of Corticospinal Excitability of Hand Muscles during Numerical Judgment

  • Authors:

  • Marc Sato;Luigi Cattaneo;Giacomo Rizzolatti;Vittorio Gallese

  • Affiliations:

  • -;-;-;-

  • Venue:
  • Journal of Cognitive Neuroscience
  • Year:
  • 2007

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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.