From normal brain and behavior to schizophrenia

Abstract

An outstanding problem in psychology and neuroscience concerns how to link discoveries about brain mechanisms to the behaviors that they control. A related problem in psychiatry is to understand how abnormal behaviors arise from breakdowns in the brain mechanisms that govern normal behaviors. During the past few decades, neural models have been getting developed of how normal cognitive and emotional processes learn from the environment, focus attention and act upon motivationally important events, and cope with unexpected events. When arousal or volitional signals in these models are suitably altered, they give rise to symptoms that strikingly resemble negative and positive symptoms of schizophrenia, including flat affect, impoverishment of will, attentional problems, loss of a theory of mind, thought derailment, hallucinations, and delusions. These models thus suggest how an imbalance that is created in otherwise normal brain mechanisms can ramify throughout the brain to create the clinical symptoms that are observed.