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Schizophrenia Research and Treatment
Volume 2012, Article ID 176290, 12 pages
http://dx.doi.org/10.1155/2012/176290
Research Article

Faulty Suppression of Irrelevant Material in Patients with Thought Disorder Linked to Attenuated Frontotemporal Activation

1Department of Psychosis Studies, Institute of Psychiatry, King’s College London, London, UK
2NIF, Functional Neuroimaging, Lab/LIM 44, Instituto de Radiologia, University of Sao Paulo, Sao Paulo, Brazil
3Warwick Medical School, University of Warwick, Coventry UK and Psychosis Clinical Academic Group, Coventry, UK
4Department of Neuroimaging, Institute of Psychiatry, King’s College London, London, UK
5Marburg University, Marburg, Germany
6Department of Psychology, Institute of Psychiatry, King’s College London, London, UK

Received 15 November 2011; Accepted 23 December 2011

Academic Editor: Christoph Mulert

Copyright © 2012 S. M. Arcuri et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Formal thought disorder is a feature schizophrenia that manifests as disorganized, incoherent speech, and is associated with a poor clinical outcome. The neurocognitive basis of this symptom is unclear but it is thought to involve an impairment in semantic processing classically described as a loosening of meaningful associations. Using a paradigm derived from the n400 event-related, potential, we examined the extent to which regional activation during semantic processing is altered in schizophrenic patients with formal thought disorder. Ten healthy control and 18 schizophrenic participants (9 with and 9 without formal thought disorder) performed a semantic decision sentence task during an event-related functional magnetic resonance imaging experiment. We employed analysis of variance to estimate the main effects of semantic congruency and groups on activation and specific effects of formal thought disorder were addressed using post-hoc comparisons. We found that the frontotemporal network, normally engaged by a semantic decision task, was underactivated in schizophrenia, particularly in patients with FTD. This network is implicated in the inhibition of automatically primed stimuli and impairment of its function interferes with language processing and contributes to the production of incoherent speech.