The Priming Method: Imaging Unconscious Repetition Priming Reveals an Abstract Representation of Number in the Parietal Lobes

Authors: Naccache L.; Dehaene S.

Source: Cerebral Cortex, Volume 11, Number 10, October 2001 , pp. 966-974(9)

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Abstract:

Most of the current brain imaging methods are limited by the low spatial resolution of neuroimaging techniques and remain unable to measure activity at the scale of single neurons or small columns of neurons, which are the coding elements of the nervous system. In this work we have adapted the priming method, an emerging research strategy that can overcome some of these spatial limitations, to investigate the coding of numerical quantities in the human brain. This approach combines the logic of psychological priming experiments with the recently discovered neurophysiological phenomenon called repetition suppression (RS). In each trial, while subjects perform a constant task, a subliminal prime is presented prior to each target. By varying the relationship between prime and target, one can detect which brain areas present RS specifically for any given level of prime–target repetition. We first expose the general logic, potential and limitations of the priming method and then illustrate it by demonstrating that a region of parietal cortex is coding for numbers at the quantity level, independently of other stimulus attributes, and that this region processes both consciously and unconsciously perceived stimuli.

Document Type: Original article

Affiliations: 1: Unité INSERM 334, Service Hospitalier Frédéric Joliot, CEA/DRM/DSV, 4 Place du Général Leclerc, F-91401 Orsay Cedex, France

Publication date: 2001-10-01

More about this publication?

Cerebral Cortex publishes papers on the development, organization, plasticity, and function of the cerebral cortex, including the hippocampus. Studies with clear relevance to the cerebral cortex, such as the thalamocortical relationship or cortico-subcortical interactions, are also included.