Background, Aims, and Methods:

Auditory hallucinations, the experience of external speech when none is present, are a cardinal symptom of schizophrenia. Recent functional neuroimaging and structural neuroanatomic studies of hallucinations have identified dysfunctions and deficits in the auditory cortex and middle temporal gyrus, centers of the brain involved in language production and comprehension. We will record ERPs and fMRI in parallel studies while subjects talk and are presented with spoken words.

The diverse symptoms of schizophrenia have been explained as deficits at both the sensory or input side and at the output side including monitoring thought and actions. Deficits in input may include a "defective filter", or gating failure producing sensory overload, cognitive fragmentation and thought disorder. Deficits in output may include misperception of thoughts as hallucinations and one's own actions as being under alien control, as well as the negative symptoms of poverty of thought and action. We will record ERPs and fMRI in parallel studies while subjects engage in visual vigilance tasks.