Attention and Visual Perception in Schizophrenia: A Functional Magnetic Resonance Imaging (fMRI) Study

Attention and Grouping of Visual Information: What is Disturbed in Patients With Schizophrenia?

The main objective of the study is to contribute to a better understanding of the physiopathology of schizophrenia, by studying causal relationships between cognitive deficits and the neurobiological basis for these deficits. Processing visual information involves both automatic grouping processes and control processes. Automatic grouping processes allow the building of a global configuration from local contour information. It is necessary in order to recognize objects. Control processes allow tending to and prioritizing information parts. The paradigm the investigators use allows to dissociate these processes, and is used in order to characterize the impairments observed in patients with schizophrenia. It is adapted to fMRI in order to explore the neurobiological basis of the deficits. The investigators will examine whether functional disconnectivity between activated areas subtend the impairments observed in patients.

Inclusion Criteria:

• Patients with schizophrenia (DSM-IV criteria)
• Healthy controls matched with patients on age, sex and education level
• Ages 18 to 50
• Signed informed consent
• Right-handed

Exclusion Criteria:

• No severe somatic illness
• No invalidating sensory disease
• No drug abuse, as defined by DSM-IV criteria
• No general anaesthesia in the past 3 months
• No intake of drugs affecting the CNS, except for patients