Trait and State Markers of Schizophrenia in Visual Processing

Abstract

A shift in recent neuropsychiatric research has led to the identification and characterization of trait and state markers which are intrinsic to the inner workings of the brain, and suitable to serve as targets for detection, treatment, and prevention of psychiatric disorders. A trait marker represents the properties of the biological and behavioral processes that play an antecedent, and possibly causal, role in the pathophysiology of the disorder, whereas a state marker reflects the status of clinical manifestations in patients. The established connections among visual processing, brain function, and the abnormal behaviors in patients suggest that certain visual responses are useful candidates for such markers. A series of visual processing studies has begun to address the question of what types of visual functions can serve as trait or state markers. In the case of schizophrenia, evaluating clinically unaffected relatives of schizophrenia patients and patients with bipolar disorder can provide information on the relationship between a schizophrenic disposition and visual response traits. It has been found that motion integration is dysfunctional in schizophrenia patients but not in their relatives or in bipolar patients, whereas motion discrimination is dysfunctional in schizophrenia patients and their relatives, but not in bipolar patients. By synthesizing these findings, this chapter suggests that visual processing trait and state markers of schizophrenia can be distinguished, as illustrated in the examples of motion discrimination vs. motion integration. Identifying and distinguishing these markers is useful for developing pharmacological and behavioral interventions for patients with schizophrenia