Cognitive deficits in schizophrenia: prefrontal dysfunction and functional decoupling

Disorders from the schizophrenia spectrum - particularly schizophrenia - are often associated with cognitive deficits. Attention, vigilance and higher cognitive functions such as working memory, executive functions, episodic and semantic memory as well as language are impaired in patients with schizophrenia. Moreover, these impaired domains are thought to be reliable predictors throughout the course of the disease. For three decades, impaired working memory and executive functions have been empirically associated with abnormalities of the prefrontal cortex. However, the advent of functional imaging techniques using cognitive activation paradigms has challenged the concept of 'hypofrontality' in schizophrenia. Recent work suggests that the cognitive deficits seen in schizophrenic patients maybe not the result of an isolated dysfunction of the prefrontal cortex, but rather a consequence from a functionally decoupled frontotemporal network. This finding maybe specific for schizophrenia and may prove to be useful for additional diagnostic application.