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Review
. 2004 Mar;29(2):89-98.

Semantics and N400: insights for schizophrenia

Namita Kumar  1 , J Bruno Debruille
Affiliations
Review

Semantics and N400: insights for schizophrenia

Namita Kumar et al. J Psychiatry Neurosci. 2004 Mar.

Abstract
in English, French

Thought disorder is a hallmark symptom of schizophrenia, which often leads to deficits in social functioning. Some aspects of this cognitive dysfunction are the result of abnormal characteristics in the semantic processes of patients. These abnormalities exist not only at the discourse production level, but at the discourse comprehension level as well. The recording and analysis of event-related potentials has greatly advanced the investigation of the processing of linguistic information. One particular component of event-related potentials, N400, indexes semantic processing. Whereas all meaningful words elicit an N400, the amplitude of this component is much greater in response to words that are unexpected in a given context. As such, it is thought to reflect processes involved in contextual integration, which is the key to correct comprehension. N400 has been found to be abnormal in patients with schizophrenia when compared with healthy controls and, thus, may point toward the underlying cause of semantic deficits of patients with thought disorder.

Le trouble de la pensée est un symptôme caractéristique de la schizophrénie, qui entraÎne souvent des déficits du fonctionnement social. Certains aspects de ce dysfonctionnement cognitif résultent des caractéristiques anormales des processus sémantiques des patients. Ces anomalies existent au niveau non seulement de la production, mais aussi de la compréhension du discours. La consignation et l'analyse de potentiels reliés à des événements a fait progresser considérablement l'étude du traitement de l'information linguistique. Un élément constituant particulier des potentiels reliés aux événements, l'élément N400, indexe le traitement sémantique. Alors que tous les mots significatifs provoquent un N400, l'amplitude de cet élément constituant est beaucoup plus grande face à des mots inattendus dans un contexte donné. C'est pourquoi on croit qu'il reflète des processus intervenant dans l'intégration contextuelle, ce qui constitue la clé de la compréhension correcte. On a constaté une anomalie de l'élément N400 chez des patients atteints de schizophrénie comparativement à des témoins en bonne santé, ce qui pourrait donc indiquer la cause sous-jacente des déficits sémantiques chez les patients atteints d'un trouble de la pensée.

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Figures

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Fig. 1: Classic model: a schematic representation of concept relatedness in a stereotypical fragment of human memory (where a shorter line represents greater relatedness). Reprinted with permission from the American Psychological Association (Psychol Rev 1975;82:407-28).
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Fig. 2: An example of sentences with a high degree of contextual constraint and with varying degrees (high/low) of Cloze probability of the sentence-ending word (A). Grand average event-related potentials (ERPs) from the Pz electrode in response to sentence-ending words show a large N400 in response to low Cloze probability words and no N400 to high-probability words (B). Adapted with permission from Macmillan Publishers (Nature 1984;307:161-3. www.nature.com).
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Fig. 3: Grand average ERPs from the Pz electrode in response to sentence-ending words show an enhanced N400 in response to sentences that make sense (upper) and to nonsensical sentences (lower) in patients with schizophrenia compared with healthy controls. Dashed lines = patients with schizophrenia; solid lines = healthy controls. Adapted with permission from the American Psychiatric Association (Am J Psychiatry 1997;154:640-6. http://ajp.psychiatryonline.org).
See this image and copyright information in PMC

References

    1. Bleuler E. Dementia praecox or the group of schizophrenias [Translated by J. Zinkin]. New York: International Universities Press; 1950.
    1. Haimo SF, Holzman PS. Thought disorder in schizophrenics and normal controls: social class and race differences. J Consult Clin Psychol 1979;47(5):963-7. - PubMed
    1. Andreasen NC, Grove WM. Thought, language, and communication in schizophrenia: diagnosis and prognosis. Schizophr Bull 1986;12(3):348-59. - PubMed
    1. Gambini O, Campana A, Macciardi F, Scarone S. A preliminary report of a strong genetic component for thought disorder in normals. A twin study. Neuropsychobiology 1997;36(1):13-8. - PubMed
    1. Brown CM, Hagoort P, Kutas M. Postlexical integration processes in language comprehension: evidence from brain-imaging research. In: Gazzaniga MS, editor. The new cognitive neurosciences. Cambridge: MIT Press; 2000. p. 881-95.

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