Background: Explaining the diversity of symptoms that occur in schizophrenia is a major conceptual challenge. Perhaps the most powerful strategy is to identify a fundamental cognitive process and/or a fundamental neural circuit.
Methods: Convergent data from our research group in Iowa and from investigators in other centres are summarized.
Results: The thalamus plays a key role in information processing. A defect in circuitry connecting the thalamus, frontal cortex, and cerebellum could explain a wide range of symptoms. Neuropathology and imaging studies suggest that patients with schizophrenia may have abnormalities in this circuitry.
Conclusion: The fundamental deficit in schizophrenia may be conceptualized as a "cognitive dysmetria" characterized by impairments in coordinating the perception, encoding, retrieval, and prioritization of experience and information.