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Conscious and subliminal conflicts in normal subjects and patients with schizophrenia: the role of the anterior cingulate - PubMed

  • ️Wed Jan 01 2003

Conscious and subliminal conflicts in normal subjects and patients with schizophrenia: the role of the anterior cingulate

Stanislas Dehaene et al. Proc Natl Acad Sci U S A. 2003.

Abstract

The human anterior cingulate cortex (ACC), which is active during conflict-monitoring tasks, is thought to participate with prefrontal cortices in a distributed network for conscious self-regulation. This hypothesis predicts that conflict-related ACC activation should occur only when the conflicting stimuli are consciously perceived. To dissociate conflict from consciousness, we measured the behavioral and brain imaging correlates of a motor conflict induced by task-irrelevant subliminal or conscious primes. The same task was studied in normal subjects and in patients with schizophrenia in whom the ACC and prefrontal cortex are thought to be dysfunctional. Conscious, but not subliminal, conflict affected anterior cingulate activity in normal subjects. Furthermore, patients with schizophrenia, who exhibited a hypoactivation of the ACC and other frontal, temporal, hippocampal, and striatal sites, showed impaired conscious priming but normal subliminal priming. Those findings suggest that subliminal conflicts are resolved without ACC contribution and that the ACC participates in a distributed conscious control network that is altered in schizophrenia.

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Figures

Fig. 1.
Fig. 1.

Experimental paradigm. Subjects compared a 200-ms target number to a fixed numerical standard. Each target was preceded by a fast presentation of another number that served as a prime. In different blocks, the prime could be masked by random consonant strings (Left), or it could be visible and had to be actively ignored (Right).

Fig. 2.
Fig. 2.

Behavioral performance in number comparison in control subjects and in patients with schizophrenia (mean effect size in milliseconds ± SE). Both groups show identical effects of numerical distance, number notation, and subliminal priming. However, they differed in the unmasked priming effect, which required conscious control of interference. Patients were also severely slowed in the unmasked condition compared with the masked condition.

Fig. 3.
Fig. 3.

Reduced overall activation of the anterior cingulate and frontal cortices, relative to the intertrial resting period, in patients relative to controls.

Fig. 4.
Fig. 4.

Effect of conscious conflict in the anterior cingulate in controls and in patients. (A Upper) Congruity × visibility interaction in normal subjects, showing greater activation in ACC and other brain regions on incongruent trials than on congruent trials, but only when the prime was unmasked. This effect was not found in patients, thus resulting in a triple-interaction group × congruity × visibility (A Lower). Curves show the mean percent signal change in the left ACC as a function of time (B), revealing a hypoactivation and an absence of conscious conflict effect in the patients.

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References

    1. Paus, T., Koski, L., Caramanos, Z. & Westbury, C. (1998) NeuroReport 9, R37-R47. - PubMed
    1. Bush, G., Luu, P. & Posner, M. I. (2000) Trends Cogn. Sci. 4, 215-222. - PubMed
    1. Botvinick, M., Nystrom, L. E., Fissell, K., Carter, C. S. & Cohen, J. D. (1999) Nature 402, 179-181. - PubMed
    1. Cohen, J. D., Botvinick, M. & Carter, C. S. (2000) Nat. Neurosci. 3, 421-423. - PubMed
    1. Carter, C. S., Macdonald, A. M., Botvinick, M., Ross, L. L., Stenger, V. A., Noll, D. & Cohen, J. D. (2000) Proc. Natl. Acad. Sci. USA 97, 1944-1948. - PMC - PubMed

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