Brain Advance Access originally published online on March 3, 2008
Brain 2008 131(4):962-970; doi:10.1093/brain/awn032
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The architecture of cognitive control in schizophrenia
1Centre de Neurosciences Cognitives, Université de Lyon, CNRS, 69675 Lyon, 2Centre Hospitalier le Vinatier and Université Claude Bernard, 69675 Lyon, 3INSERM, Université Pierre et Marie Curie and Ecole Normale Supérieure, 75005 Paris, 4Service Hospitalo-Universitaire de Psychiatrie, CHU Sainte-Marguerite, 13009 Marseille and 5Equipe de Probabilités, Statistiques et Physique mathématique, Université Claude Bernard, CNRS, 69366 Lyon, France
Correspondence to: Valérian Chambon and Chlöé Farrer, Centre de Neuroscience Cognitive, UMR 5229 CNRS, 67, bd Pinel, 69 675 BRON Cedex, France E-mail: valerian.chambon{at}isc.cnrs.fr; farrer{at}isc.cnrs.fr
Executive dysfunctions have long been considered a common feature of schizophrenia. However, due to their extreme heterogeneity, it is not clear whether these impairments take place at a particular level of executive functioning or non-specifically affect various aspects of behavioural control. To answer this question, we used an experimental paradigm based upon a multistage model of prefrontal executive function. This model postulates that cognitive control is organized in three hierarchically ordered control processes, operating with respect to the perceptual context (sensory and contextual controls) or the temporal episode in which the person is acting (episodic control). Twenty-four patients with schizophrenia and 24 non-psychiatric controls participated in two distinct experiments designed to separately assess each of these three levels of control. The results indicate that both sensory and episodic dimensions of cognitive control were spared in schizophrenic patients, but that they showed great difficulty in contextual conditions, as the selection of the appropriate response among competitive ones required taking into account information related to perceptual context. Contextual control can be considered as a set of executive processes mediating the hierarchical organization of behaviour. Patients deficit in cognitive control therefore reflects a specific problem in the hierarchical control of action, leading to the selection of inappropriate behavioural representations for ongoing action plans. We also showed that this impairment was a good predictor of disorganization syndrome scores, suggesting that these clinical manifestations might result from a deficit in the combination or selection of hierarchically organized action representations.
Key Words: cognitive control; cascade model; schizophrenia; context processing; disorganization syndrome
Abbreviations: EPs, error percentages; RTs, reaction times; SR, stimulus-response; WAIS, Wechsler Adult Intelligence Scale
Received July 11, 2007. Revised November 9, 2007. Accepted February 12, 2008.