Aberrant localization of synchronous hemodynamic activity in auditory cortex reliably characterizes schizophrenia.

BACKGROUND: Among the most prominent features of schizophrenic brains are abnormalities in auditory cortex structure and function, particularly in the superior temporal gyrus (STG). In this study, we attempted to examine auditory cortex function using an intrinsic, task-uncorrelated measure. METHODS: Using functional magnetic resonance imaging data, we calculated synchronous hemodynamic independent maps (SHIMs) of auditory cortex in patients with schizophrenia and matched healthy control subjects while they performed an auditory oddball task. RESULTS: Patient SHIMs revealed greater synchrony in ventral and medial STG regions (including auditory association Brodmann area [BA] 42); control SHIMs had greater synchrony in dorsal and lateral STG regions (which did not include BA 42). A within-participant subtractive comparison of these two sets of regions differentiated schizophrenic from healthy control subjects with 97% accuracy initially (further validated by a retest of the healthy control subjects) and performed with 94% accuracy in a confirmatory study of new subjects scanned at a different site. CONCLUSIONS: These results shed new light on STG functional differences in schizophrenia, suggest that aberrant patterns of coherence in temporal lobe cortical regions are a cardinal abnormality in schizophrenia, and have the potential to provide a powerful, quantitative clinical tool for the assessment of schizophrenia.