Dysfunctions in multiple interrelated systems as the neurobiological bases of schizophrenic symptom clusters

The absence of an animal model that accurately approximates schizophrenia limits current research into the pathophysiology of this disorder. Obviously, the cognitive disturbances associated with schizophrenia are difficult to evaluate in laboratory animals. Nonetheless, animal studies have provided insight into the anatomy and physiology of the brain systems that have been implicated in schizophrenia. These studies also suggest how brain systems may be involved in information processing in normal and pathological conditions. Thus, a careful assessment of the properties and functions of the brain regions suggested to be involved in schizophrenic symptoms has been a primary objective in several laboratories. In this review, we discuss the interactions among the brain regions implicated in schizophrenia--the ventral striatum, prefrontal cortex, hippocampus, and dopamine systems--and provide an integrative model linking altered function in these regions with specific clusters of symptoms of schizophrenia.