Cerebral Dysfunctions in Schizophrenia Patients: Characterization of Relevant Factors of Influence

For the valid interpretation of functional neuroimaging results of dysfunctions as well as reorganization processes in schizophrenia patients, several methodological as well as conceptual factors are of relevance. Quality assurance procedures are especially important for multi-center studies but also in general for data acquisition and sequence optimization, especially with respect to investigations of emotional processes focusing on subcortical structures such as the amygdala. Furthermore, existing neuropsychological paradigms have to be evaluated for the neuroimaging environment or/and new neurobehavioral probes have to be developed and standardized, since they constitute the basis for valid results. Gender differences, task characteristics, influence of medication and sample characteristics are further factors of influence that have to be analyzed. Data acquired from different samples of healthy subjects and schizophrenia patients clarify the relevance of these factors for fMRI results. Cognitive and emotional processes, their interaction as well as dysfunctions in schizophrenia have been investigated with fMRI. In an advanced approach we aimed at differentiating trait and state components of these dysfunctions by investigating relatives of patients, first-episode patients or patients with early-onset psychoses, which point to genetic influences and an early appearance of dysfunctions. Equally, long-term investigations of the illness course and the therapeutic effects of pharmacological as well as psychological interventions on the dysfunctional cerebral networks have been performed. Hypo- and hyperactivations emerged in a subcortical-limbic as well as cortical network in dependence on the task requirements. Results of the longitudinal studies document the therapeutic effects, normally seen on a behavioral level, in the underlying neuronal substrates and demonstrate the specific efficacy of pharmacological and behavioral therapy. They point to the benefit of neuroimaging procedures for clinical as well as basic research.