A cognitive neuroscience view of schizophrenic thought disorder.

The experimental association psychology approach to mental associations has been the conceptual background for the concept of schizophrenia. Cognitive neuroscience methods and concepts can be used to study various forms of schizophrenic thought disorder. In particular, the concepts of semantic associative and working memory can be applied fruitfully to schizophrenia research. Semantic associative networks can be simulated with self-organizing feature maps. Dysfunctional lexical access can be modeled in terms of low signal-to-noise ratio in intra- or between-network information processing. Evidence for the crucial role of dopamine in this function is presented, and a general neurocomputational model of schizophrenic thought disorder is developed. This model capitalizes on basic aspects of neural information processing (i.e., neuromodulation and neuroplasticity) and allows a parsimonious explanation of a number of otherwise inexplicable or unrelated clinical phenomena and experimental results.