Schizophrenia--a Disorder of the Corollary Discharge Systems That Integrate the Motor Systems of Thought with the Sensory Systems of Consciousness

Background: In spite of intensive research, no causal anatomical lesion has been found in schizophrenia. It may instead be caused by malfunctioning circuits in the corollary discharge, feed forward (CD-FF) systems of thought.

Aims: To integrate with the CD-FF hypothesis recent data showing that subcortical motor systems participate in thinking.

Methods: We review CD-FF concepts in relation to recent evidence that 'motor' brain structures participate in cognitive processing.

Results: Malfunctioning of CD-FF systems that integrate thinking and consciousness could produce auditory hallucinations, delusions and disorganised thought.

Conclusions: We hypothesise that the pathophysiology of schizophrenia lies in integrative circuits of basal ganglia, thalamus and frontal cortex. Fruitful research directions would include elucidation of CD-FF circuits at even higher brain levels, the behaviour of these circuits during dreaming, and their responses to late maturational events including synaptic elimination.