Objectives: To extend the hypothesis that late auditory EP shifts represent pathophysiologcial markers in schizophrenia. Methods: Early negative (±100 μs) and late positive (>300 ms) auditory oddball and CNV responses are topographically compared in 3 medicated schizophrenic subtypes.

Results: Only late cortical responses differentiate between paranoid, residual and disorganised schizophrenia. Core features of the deficit residual state encompass low-voltage N2P3 responses and missing central initial CNV components. Both paranoid and disorganised schizophrenics show a distinctive reactivity of the frontal cortex. Paranoid schizophrenia is characterized by an extensive frontal spread of the task-related P3 response. Disorganised schizophrenia shows a specifically increased frontal CNV component indicating a nonspecific arousal reaction.

Conclusion: Combinations of late auditory EP-patterns fairly fit with the cognitive/behavioral status observed in schizophrenia spectrum disorders.

The neural mechanisms of deviancy and target detection were investigated by combining high density event-related potential (ERP) recordings with functional magnetic resonance imaging (fMRI). ERP and fMRI responses were recorded using the same paradigm and the same subjects. Unattended deviants elicited a mismatch negativity (MMN) in the ERP. In the fMRI data, activations of transverse/superior temporal gyri bilateral were found. Attended deviants generated an MMN followed by an N2/P3b complex. For this condition, fMRI activations in both superior temporal gyri and the neostriatum were found. These activations were taken as neuroanatomical constraints for the localization of equivalent current dipoles. Inverse solutions for dipole orientation provide evidence for significant activation close to Heschl's gyri during deviancy processing in the 110–160-ms time interval (MMN), whereas target detection could be modeled by two dipoles in the superior temporal gyrus between 320 and 380 ms.