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Cerebral mechanisms of word masking and unconscious repetition priming


We used functional magnetic resonance imaging (fMRI) and event-related potentials (ERPs) to visualize the cerebral processing of unseen masked words. Within the areas associated with conscious reading, masked words activated left extrastriate, fusiform and precentral areas. Furthermore, masked words reduced the amount of activation evoked by a subsequent conscious presentation of the same word. In the left fusiform gyrus, this repetition suppression phenomenon was independent of whether the prime and target shared the same case, indicating that case-independent information about letter strings was extracted unconsciously. In comparison to an unmasked situation, however, the activation evoked by masked words was drastically reduced and was undetectable in prefrontal and parietal areas, correlating with participants' inability to report the masked words.

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Figure 1: Design and behavioral results of experiment 1.
Figure 2: fMRI activations to visible and masked words in experiment 1.
Figure 3: Cartography of ERPs in reponse to visible words and to masked words.
Figure 4: Design and behavioral results of experiment 2.
Figure 5: fMRI correlates of unconscious repetition priming.


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We thank J.-P. Changeux, C. Pallier and L. Spelke for useful comments. This project was supported by the McDonnell Foundation.

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Correspondence to Stanislas Dehaene.

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Dehaene, S., Naccache, L., Cohen, L. et al. Cerebral mechanisms of word masking and unconscious repetition priming. Nat Neurosci 4, 752–758 (2001).

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